An Alfin-like gene from Atriplex hortensis enhances salt and drought tolerance and abscisic acid response in transgenic Arabidopsis

Phosphorylation of ZmAL14 by ZmSnRK2.2 regulates drought resistance through derepressing ZmROP8 expression

Drought stress has negative effects on crop growth and production. Characterization of transcription factors that regulate the expression of drought-responsive genes is critical for understanding the transcriptional regulatory networks in response to drought, which facilitates the improvement of crop drought tolerance. Here, we identified an Alfin-like (AL) family gene ZmAL14 that negatively regulates drought resistance. Overexpression of ZmAL14 exhibits susceptibility to drought while mutation of ZmAL14 enhances drought resistance. An abscisic acid (ABA)-activated protein kinase ZmSnRK2.2 interacts and phosphorylates ZmAL14 at T38 residue. Knockout of ZmSnRK2.2 gene decreases drought resistance of maize. A dehydration-induced Rho-like small guanosine triphosphatase gene ZmROP8 is directly targeted and repressed by ZmAL14. Phosphorylation of ZmAL14 by ZmSnRK2.2 prevents its binding to the ZmROP8 promoter, thereby releasing the repression of ZmROP8 transcription. Overexpression of ZmROP8 stimulates peroxidase activity and reduces hydrogen peroxide accumulation after drought treatment. Collectively, our study indicates that ZmAL14 is a negative regulator of drought resistance, which can be phosphorylated by ZmSnRK2.2 through the ABA signaling pathway, thus preventing its suppression on ZmROP8 transcription during drought stress response.

Involvement of Alfin-Like Transcription Factors in Plant Development and Stress Response

Alfin-like (AL) proteins are an important class of transcription factor (TF) widely distributed in eukaryotes and play vital roles in many aspects of plant growth and development. AL proteins contain an Alfin-like domain and a specific PHD-finger structure domain at the N-terminus and C-terminus, respectively. The PHD domain can bind to a specific (C/A) CAC element in the promoter region and affect plant growth and development by regulating the expression of functional genes. This review describes a variety of AL transcription factors that have been isolated and characterized in Arabidopsis thaliana, Brassica rapa, Zea mays, Brassica oleracea, Solanum lycopersicum, Populus trichocarpa, Pyrus bretschenedri, Malus domestica, and other species. These studies have focused mainly on plant growth and development, different abiotic stress responses, different hormonal stress responses, and stress responses after exposure to pathogenic bacteria. However, studies on the molecular functional mechanisms of Alfin-like transcription factors and the interactions between different signaling pathways are rare. In this review, we performed phylogenetic analysis, cluster analysis, and motif analysis based on A. thaliana sequences. We summarize the structural characteristics of AL transcription factors in different plant species and the diverse functions of AL transcription factors in plant development and stress regulation responses. The aim of this study was to provide a reference for further application of the functions and mechanisms of action of the AL protein family in plants.

PHD finger proteins function in plant development and abiotic stress responses: an overview

The plant homeodomain (PHD) finger with a conserved Cys4-His-Cys3 motif is a common zinc-binding domain, which is widely present in all eukaryotic genomes. The PHD finger is the "reader" domain of methylation marks in histone H3 and plays a role in the regulation of gene expression patterns. Numerous proteins containing the PHD finger have been found in plants. In this review, we summarize the functional studies on PHD finger proteins in plant growth and development and responses to abiotic stresses in recent years. Some PHD finger proteins, such as VIN3, VILs, and Ehd3, are involved in the regulation of flowering time, while some PHD finger proteins participate in the pollen development, for example, MS, TIP3, and MMD1. Furthermore, other PHD finger proteins regulate the plant tolerance to abiotic stresses, including Alfin1, ALs, and AtSIZ1. Research suggests that PHD finger proteins, as an essential transcription regulator family, play critical roles in various plant biological processes, which is helpful in understanding the molecular mechanisms of novel PHD finger proteins to perform specific function.

Identification and Expression Analysis of the Alfin-like Gene Family in Tomato and the Role of SlAL3 in Salt and Drought Stresses

Alfin-like (AL) transcription factors are a family of plant-specific genes with a PHD-finger-like structural domain at the C-terminus and a DUF3594 structural domain at the N-terminus that play important roles in plant development and stress response. In the present study, genome-wide identification and analysis were performed of the AL protein family in cultivated tomato (Solanum lycopersicum) and three wild relatives (S. pennellii, S. pimpinellifolium, and S. lycopersicoides) to evaluate their response to different abiotic stresses. A total of 39 ALs were identified and classified into four groups and based on phylogenetic tree and evolutionary analysis were shown to have formed prior to the differentiation of monocotyledons and dicots. Moreover, cis-acting element analysis revealed that various phytohormone response and abiotic stress response elements were highly existed in tomato. In addition, further analysis of the SlAL3 gene revealed that its expression was induced by drought and salt stresses and localized to the nucleus. In conclusion, our findings concerning AL genes provide useful information for further studies on their functions and regulatory mechanisms and provide theoretical references for studying AL gene response to abiotic stresses in plants.

Genetic analysis of grapevine root system architecture and loci associated gene networks

Own-rooted grapevines and grapevine rootstocks are vegetatively propagated from cuttings and have an adventitious root system. Unraveling the genetic underpinnings of the adventitious root system architecture (RSA) is important for improving own-rooted and grafted grapevine sustainability for a changing climate. Grapevine RSA genetic analysis was conducted in an Vitis sp. 'VRS-F2' population. Nine root morphology, three total root system morphology, and two biomass traits that contribute to root anchorage and water and nutrient uptake were phenotyped. Quantitative trait loci (QTL) analysis was performed using a high density integrated GBS and rhAmpSeq genetic map. Thirty-one QTL were detected for eleven of the RSA traits (surface area, root volume, total root length, fresh weight, number of tips, forks or links, longest root and average root diameter, link length, and link surface area) revealing many small effects. Several QTL were colocated on chromosomes 1, 9, 13, 18, and 19. QTL with identical peak positions on chromosomes 1 or 13 were enriched for AP2-EREBP, AS2, C2C2-CO, HMG, and MYB transcription factors, and QTL on chromosomes 9 or 13 were enriched for the ALFIN-LIKE transcription factor and regulation of autophagy pathways. QTL modeling for individual root traits identified eight models explaining 13.2 to 31.8% of the phenotypic variation. 'Seyval blanc' was the grandparent contributing to the allele models that included a greater surface area, total root length, and branching (number of forks and links) traits promoting a greater root density. In contrast, V. riparia 'Manitoba 37' contributed the allele for greater average branch length (link length) and diameter, promoting a less dense elongated root system with thicker roots. LATERAL ORGAN BOUNDARY DOMAIN (LBD or AS2/LOB) and the PROTODERMAL FACTOR (PFD2 and ANL2) were identified as important candidate genes in the enriched pathways underlying the hotspots for grapevine adventitious RSA. The combined QTL hotspot and trait modeling identified transcription factors, cell cycle and circadian rhythm genes with a known role in root cell and epidermal layer differentiation, lateral root development and cortex thickness. These genes are candidates for tailoring grapevine root system texture, density and length in breeding programs.

Genome-wide characterization of Alfin-like (AL) genes in apple and functional identification of MdAL4 in response to drought stress

Eleven Alfin-like (AL) genes were obtained from apple and MdAL4 was selected for improving drought stress tolerance of transgenic apple callus and Arabidopsis. Drought is an important environmental factor affecting plant growth all over the world. Alfin-like (AL) have well-documented functions in abiotic stress response, but their drought stress tolerance in apple (Malus domestica) are poorly understood. According to the transcriptome data, 11 MdAL genes containing conserved Alfin and PHD-finger domain were identified in apple and divided into three subgroups with a total of 35 members from different species. Subsequently, gene structures, conserved amino acid sequences, promoter cis-acting elements, and gene evolution events were analyzed. Based on differential expression of MdALs in response to abiotic stresses, MdAL4, which was highly expressed under drought, was further cloned and investigated. MdAL4 encoding nuclear-localized protein conferred enhanced drought tolerance in overexpressing transgenic calli of apple 'Orin'. Moreover, the ectopic expression of MdAL4 improved the drought tolerance of transgenic Arabidopsis, as judged from remarkably decreased malonaldehyde (MDA) content and electrolyte leakage in MdAL4 overexpressing plants relative to WT. Furthermore, MdAL4 possibly could bind to promoter regions of ROS-scavenging and stress-related genes to improve drought tolerance. Additionally, we found in silico evidence that three proteins containing the WD40 domain that interact with MdAL4. Based on these results, MdAL4 was identified as a positive regulator for improving drought stress of apple.

Alfin-like transcription factor VqAL4 regulates a stilbene synthase to enhance powdery mildew resistance in grapevine

Resveratrol is a phytoalexin that is synthesized by stilbene synthase (STS). Resveratrol in the human diet is known to have beneficial effects on health. We previously identified six novel STS (VqNSTS) transcripts from the transcriptome data of Vitis quinquangularis accession Danfeng-2. However, the functions of and defensive mechanisms triggered by these VqNSTS transcripts remain unknown. In the present study, we demonstrate that the expression of five of these six novel members, VqNSTS2-VqNSTS6, can be induced by the powdery mildew-causing fungus Uncinula necator. Additionally, overexpression of VqNSTS4 in the V. vinifera susceptible cultivar Thompson Seedless promoted accumulation of stilbenes and enhanced resistance to U. necator by activating salicylic acid (SA) signalling. Furthermore, our results indicate that the Alfin-like (AL) transcription factor VqAL4 can directly bind to the G-rich element (CACCTC) in the VqNSTS4 promoter and activate gene expression. Moreover, overexpression of VqAL4 in Thompson Seedless enhanced resistance to U. necator by promoting stilbene accumulation and activating SA signalling. Conversely, RNA interference-mediated silencing of VqNSTS4 and VqAL4 resulted in increased susceptibility to U. necator. Collectively, our results reveal that VqNSTS4, regulated by VqAL4, enhances grapevine resistance to powdery mildew by activating SA signalling. Our findings may be useful to improve disease resistance in perennial fruit trees.

The MAPK-Alfin-like 7 module negatively regulates ROS scavenging genes to promote NLR-mediated immunity

Nucleotide-binding leucine-rich repeat (NLR) receptor-mediated immunity includes rapid production of reactive oxygen species (ROS) and transcriptional reprogramming, which is controlled by transcription factors (TFs). Although some TFs have been reported to participate in NLR-mediated immune response, most TFs are transcriptional activators, and whether and how transcriptional repressors regulate NLR-mediated plant defenses remains largely unknown. Here, we show that the Alfin-like 7 (AL7) interacts with N NLR and functions as a transcriptional repressor. Knockdown and knockout of AL7 compromise N NLR-mediated resistance against tobacco mosaic virus, whereas AL7 overexpression enhances defense, indicating a positive regulatory role for AL7 in immunity. AL7 binds to the promoters of ROS scavenging genes to inhibit their transcription during immune responses. Mitogen-activated protein kinases (MAPKs), salicylic acid-induced protein kinase (SIPK), and wound-induced protein kinase (WIPK) directly interact with and phosphorylate AL7, which impairs the AL7-N interaction and enhances its DNA binding activity, which promotes ROS accumulation and enables immune activation. In addition to N, AL7 is also required for the function of other Toll interleukin 1 receptor/nucleotide-binding/leucine-rich repeats (TNLs) including Roq1 and RRS1-R/RPS4. Our findings reveal a hitherto unknown MAPK-AL7 module that negatively regulates ROS scavenging genes to promote NLR-mediated immunity.

Natural variation of Alfin-like family affects seed size and drought tolerance in rice

The Alfin-like (AL) family is a group of small plant-specific transcriptional factors involved in abiotic stresses in dicotyledon. In an early study, we found an AL gene in rice that was associated with grain yield under drought stress. However, little information is known about the AL family in rice. In this study, AL genes in the rice genome were identified, and the OsAL proteins were found to locate in the nucleus and have no transcriptional self-activation activity. The expression of the OsALs was regulated by different environmental stimulations and plant hormones. Association and domestication analysis revealed that natural variation of most OsALs was significantly associated with yield traits, drought resistance and divergence in grain size in indica and japonica rice varieties. Hap1 of OsAL7.1 and Hap7 of OsAL11 were favorable haplotypes of seed weight and germination under osmotic stress. Furthermore, osal7.1 and osal11 mutants have larger seeds and are more sensitive to abscisic acid and mannitol during germination stage. Overexpressing of OsAL7.1 and OsAL11 in rice weakened the tolerance to drought in the adult stage. Thus, our work provides informative knowledge for exploring and harnessing haplotype diversity of OsALs to improve yield stability under drought stress.

Carrot DcALFIN4 and DcALFIN7 Transcription Factors Boost Carotenoid Levels and Participate Differentially in Salt Stress Tolerance When Expressed in Arabidopsis thaliana and Actinidia deliciosa

ALFIN-like transcription factors (ALs) are involved in several physiological processes such as seed germination, root development and abiotic stress responses in plants. In carrot (Daucus carota), the expression of DcPSY2, a gene encoding phytoene synthase required for carotenoid biosynthesis, is induced after salt and abscisic acid (ABA) treatment. Interestingly, the DcPSY2 promoter contains multiple ALFIN response elements. By in silico analysis, we identified two putative genes with the molecular characteristics of ALs, DcAL4 and DcAL7, in the carrot transcriptome. These genes encode nuclear proteins that transactivate reporter genes and bind to the carrot DcPSY2 promoter in yeast. The expression of both genes is induced in carrot under salt stress, especially DcAL4 which also responds to ABA treatment. Transgenic homozygous T3 Arabidopsis thaliana lines that stably express DcAL4 and DcAL7 show a higher survival rate with respect to control plants after chronic salt stress. Of note is that DcAL4 lines present a better performance in salt treatments, correlating with the expression level of DcAL4, AtPSY and AtDXR and an increase in carotenoid and chlorophyll contents. Likewise, DcAL4 transgenic kiwi (Actinidia deliciosa) lines show increased carotenoid and chlorophyll content and higher survival rate compared to control plants after chronic salt treatment. Therefore, DcAL4 and DcAL7 encode functional transcription factors, while ectopic expression of DcAL4 provides increased tolerance to salinity in Arabidopsis and Kiwi plants.

Systematic analysis of CNGCs in cotton and the positive role of GhCNGC32 and GhCNGC35 in salt tolerance

BACKGROUND

Cyclic nucleotide-gated ion channels (CNGCs) are calcium-permeable channels that participate in a variety of biological functions, such as signaling pathways, plant development, and environmental stress and stimulus responses. Nevertheless, there have been few studies on CNGC gene family in cotton.

RESULTS

In this study, a total of 114 CNGC genes were identified from the genomes of 4 cotton species. These genes clustered into 5 main groups: I, II, III, IVa, and IVb. Gene structure and protein motif analysis showed that CNGCs on the same branch were highly conserved. In addition, collinearity analysis showed that the CNGC gene family had expanded mainly by whole-genome duplication (WGD). Promoter analysis of the GhCNGCs showed that there were a large number of cis-acting elements related to abscisic acid (ABA). Combination of transcriptome data and the results of quantitative RT-PCR (qRT-PCR) analysis revealed that some GhCNGC genes were induced in response to salt and drought stress and to exogenous ABA. Virus-induced gene silencing (VIGS) experiments showed that the silencing of the GhCNGC32 and GhCNGC35 genes decreased the salt tolerance of cotton plants (TRV:00). Specifically, physiological indexes showed that the malondialdehyde (MDA) content in gene-silenced plants (TRV:GhCNGC32 and TRV:GhCNGC35) increased significantly under salt stress but that the peroxidase (POD) activity decreased. After salt stress, the expression level of ABA-related genes increased significantly, indicating that salt stress can trigger the ABA signal regulatory mechanism.

CONCLUSIONS

we comprehensively analyzed CNGC genes in four cotton species, and found that GhCNGC32 and GhCNGC35 genes play an important role in cotton salt tolerance. These results laid a foundation for the subsequent study of the involvement of cotton CNGC genes in salt tolerance.

The Memory of Rice Response to Spaceflight Stress: From the Perspective of Metabolomics and Proteomics

The stress response of plants to spaceflight has been confirmed in contemporary plants, and plants retained the memory of spaceflight through methylation reaction. However, how the progeny plants adapt to this cross-generational stress memory was rarely reported. Here, we used the ShiJian-10 retractable satellite carrying Dongnong416 rice seeds for a 12.5-day on-orbit flight and planted the F2 generation after returning to the ground. We evaluated the agronomic traits of the F2 generation plants and found that the F2 generation plants had no significant differences in plant height and number of tillers. Next, the redox state in F2 plants was evaluated, and it was found that the spaceflight broke the redox state of the F2 generation rice. In order to further illustrate the stress response caused by this redox state imbalance, we conducted proteomics and metabolomics analysis. Proteomics results showed that the redox process in F2 rice interacts with signal transduction, stress response, and other pathways, causing genome instability in the plant, leading to transcription, post-transcriptional modification, protein synthesis, protein modification, and degradation processes were suppressed. The metabolomics results showed that the metabolism of the F2 generation plants was reshaped. These metabolic pathways mainly included amino acid metabolism, sugar metabolism, cofactor and vitamin metabolism, purine metabolism, phenylpropane biosynthesis, and flavonoid metabolism. These metabolic pathways constituted a new metabolic network. This study confirmed that spaceflight affected the metabolic changes in offspring rice, which would help better understand the adaptation mechanism of plants to the space environment.

A Comprehensive Evaluation of Salt Tolerance in Tomato (Var. Ailsa Craig): Responses of Physiological and Transcriptional Changes in RBOH's and ABA Biosynthesis and Signalling Genes

Salinity is a ubiquitous stressor, depleting osmotic potential and affecting the tomato seedlings’ development and productivity. Considering this critical concern, we explored the salinity response in tomato seedlings by evaluating them under progressive salt stress duration (0, 3, 6, and 12 days). Intriguingly, besides the adverse effect of salt stress on tomato growth the findings exhibited a significant role of tomato antioxidative system, RBOH genes, ABA biosynthesis, and signaling transcription factor for establishing tolerance to salinity stress. For instance, the activities of enzymatic and non-enzymatic antioxidants continued to incline positively with the increased levels of reactive oxygen species (O₂^•−, H₂O₂), MDA, and cellular damage, suggesting the scavenging capacity of tomato seedlings against salt stress. Notably, the RBOH transcription factors activated the hydrogen peroxide-mediated signalling pathway that induced the detoxification mechanisms in tomato seedlings. Consequently, the increased gene expression of antioxidant enzymes and the corresponding ratio of non-enzymatic antioxidants AsA-GSH suggested the modulation of antioxidants to survive the salt-induced oxidative stress. In addition, the endogenous ABA level was enhanced under salinity stress, indicating higher ABA biosynthesis and signalling gene expression. Subsequently, the upregulated transcript abundance of ABA biosynthesis and signalling-related genes suggested the ABA-mediated capacity of tomato seedlings to regulate homeostasis under salt stress. The current findings have revealed fascinating responses of the tomato to survive the salt stress periods, in order to improve the abiotic stress tolerance in tomato.

Genic male sterility increases rice drought tolerance

Plant fertility and resistance to stress environments are antagonistic to each other. At booting stage, fertility is often sacrificed for survive in rice under abiotic stress. However, the relationship between fertility and resistance at molecular level remains elusive. Here, we identified a transcription factor, OsAlfin like 5, which regulates the OsTMS5 and links both the drought stress response and thermosensitive genic male sterility. The OsAL5 overexpression plants (OE-OsAL5) became sensitive to temperature owning to the OsTMS5 that the OE-OsAL5 plants were fertile under low temperature (23 °C) and sterile under high temperature (28 °C). Significantly, the survival rate of OE-OsAL5 lines was higher than that of the wide-type (WT) under drought stress. Further experiments confirmed that the OsAL5 regulated both of the OsTMS5 and the down-stream drought-related genes by binding to the 'GTGGAG' element in vivo, revealing that the OsAL5 participated both in the drought stress response and thermosensitive genic male sterility in rice. These findings open up the possibility of breeding elite TGMS lines with strong drought tolerance by manipulating the expression of OsAL5.

Global proteome response to Pb(II) toxicity in poplar using SWATH-MS-based quantitative proteomics investigation

Lead (Pb) toxicity is a growing serious environmental pollution that threatens human health and crop productivity. Poplar, as an important economic and ecological forest species, has the characteristics of fasting growth and accumulating heavy metals, which is a powerful model plant for phytoremediation. Here, a novel label-free quantitative proteomic platform of SWATH-MS was applied to detect proteome changes in poplar seedling roots following Pb treatment. In total 4388 unique proteins were identified and quantified, among which 542 proteins showed significant abundance changes upon Pb(II) exposure. Functional categorizations revealed that differentially expressed proteins (DEPs) primarily distributed in specialized biological processes. Particularly, lignin and flavonoid biosynthesis pathway were strongly activated upon Pb exposure, implicating their potential roles for Pb detoxification in poplar. Furthermore, hemicellulose and pectin related cell wall proteins exhibited increased abundances, where may function as a sequestration reservoir to reduce Pb toxicity in cytoplasm. Simultaneously, up-regulation of glutathione metabolism may serve as a protective role for Pb-induced oxidative damages in poplar. Further correlation investigation revealed an extra layer of post-transcriptional regulation during Pb response in poplar. Overall, our work represents multiply potential regulators in mediating Pb tolerance in poplar, providing molecular targets and strategies for phytoremediation.

Constitutive expression of aldose reductase 1 from Zea mays exacerbates salt and drought sensitivity of transgenic Escherichia coli and Arabidopsis

Aldose reductases (ARs) have been considered to play important roles in sorbitol biosynthesis, cellular detoxification and stress response in some plants. ARs from maize are capable of catalyzing the oxidation of sorbitol to glucose. However, little is known how maize ARs response to abiotic stresses. In this work, we cloned one isoform of maize ARs (ZmAR1), and furthermore we analyzed the roles of ZmAR1 in response to salt and drought stresses at both prokaryotic and eukaryotic levels. ZmAR1 encodes a putative 35 kDa protein that contains 310 amino acids. Under normal growth conditions, ZmAR1 was expressed in maize seedlings, and the highest expression level was found in leaves. But when seedlings were subjected to drought or salt treatment, the expression levels of ZmAR1 were significantly reduced. The constitutive expression of ZmAR1 increased the sensitivity of recombinant E. coli cells to drought and salt stresses compared with the control. Under salt and drought stresses, transgenic Arabidopsis lines displayed lower seed germination rate, shorter seedling root length, lower chlorophyll content, lower survival rate and lower antioxidant enzyme activity than wild type (WT) plants, but transgenic Arabidopsis had higher relative conductivity, higher water loss rate, and more MDA content than WT. Meanwhile, the introduction of ZmAR1 into Arabidopsis changed the expression levels of some stress-related genes. Taken together, our results suggested that ZmAR1 might act as a negative regulator in response to salt and drought stresses in Arabidopsis by reducing the sorbitol content and modulating the expression levels of some stress-related genes.

Potential function of CbuSPL and gene encoding its interacting protein during flowering in Catalpa bungei

BACKGROUND

"Bairihua", a variety of the Catalpa bungei, has a large amount of flowers and a long flowering period which make it an excellent material for flowering researches in trees. SPL is one of the hub genes that regulate both flowering transition and development.

RESULTS

SPL homologues CbuSPL9 was cloned using degenerate primers with RACE. Expression studies during flowering transition in "Bairihua" and ectopic expression in Arabidopsis showed that CbuSPL9 was functional similarly with its Arabidopsis homologues. In the next step, we used Y2H to identify the proteins that could interact with CbuSPL9. HMGA, an architectural transcriptional factor, was identified and cloned for further research. BiFC and BLI showed that CbuSPL9 could form a heterodimer with CbuHMGA in the nucleus. The expression analysis showed that CbuHMGA had a similar expression trend to that of CbuSPL9 during flowering in "Bairihua". Intriguingly, ectopic expression of CbuHMGA in Arabidopsis would lead to aberrant flowers, but did not effect flowering time.

CONCLUSIONS

Our results implied a novel pathway that CbuSPL9 regulated flowering development, but not flowering transition, with the participation of CbuHMGA. Further investments need to be done to verify the details of this pathway.

Ectopic expression of Medicago truncatula homeodomain finger protein, MtPHD6, enhances drought tolerance in Arabidopsis

BACKGROUND

The plant homeodomain (PHD) finger is a Cys4HisCys3-type zinc finger which promotes protein-protein interactions and binds to the cis-acting elements in the promoter regions of target genes. In Medicago truncatula, five PHD homologues with full-length sequence were identified. However, the detailed function of PHD genes was not fully addressed.

RESULTS

In this study, we characterized the function of MtPHD6 during plant responses to drought stress. MtPHD6 was highly induced by drought stress. Ectopic expression of MtPHD6 in Arabidopsis enhanced tolerance to osmotic and drought stresses. MtPHD6 transgenic plants exhibited decreased water loss rate, MDA and ROS contents, and increased leaf water content and antioxidant enzyme activities under drought condition. Global transcriptomic analysis revealed that MtPHD6 reprogramed transcriptional networks in transgenic plants. Expression levels of ABA receptor PYR/PYLs, ZINC FINGER, AP2/EREBP and WRKY transcription factors were mainly up-regulated after transformation of MtPHD6. Interaction network analysis showed that ZINC FINGER, AP2/EREBP and WRKY interacted with each other and downstream stress induced proteins.

CONCLUSIONS

We proposed that ZINC FINGER, AP2/EREBP and WRKY transcription factors were activated through ABA dependent and independent pathways to increase drought tolerance of MtPHD6 transgenic plants.

Transgenic crops for the agricultural improvement in Pakistan: a perspective of environmental stresses and the current status of genetically modified crops

Transgenic technologies have emerged as a powerful tool for crop improvement in terms of yield, quality, and quantity in many countries of the world. However, concerns also exist about the possible risks involved in transgenic crop cultivation. In this review, literature is analyzed to gauge the real intensity of the issues caused by environmental stresses in Pakistan. In addition, the research work on genetically modified organisms (GMOs) development and their performance is analyzed to serve as a guide for the scientists to help them select useful genes for crop transformation in Pakistan. The funding of GMOs research in Pakistan shows that it does not follow the global trend. We also present socio-economic impact of GM crops and political dimensions in the seed sector and the policies of the government. We envisage that this review provides guidelines for public and private sectors as well as the policy makers in Pakistan and in other countries that face similar environmental threats posed by the changing climate.

Evolution and conservation of polycomb repressive complex 1 core components and putative associated factors in the green lineage

Background

Polycomb group (PcG) proteins play important roles in animal and plant development and stress response. Polycomb repressive complex 1 (PRC1) and PRC2 are the key epigenetic regulators of gene expression, and are involved in almost all developmental stages. PRC1 catalyzes H2A monoubiquitination resulting in transcriptional silencing or activation. The PRC1 components in the green lineage were identified and evolution and conservation was analyzed by bioinformatics techniques. RING Finger Protein 1 (RING1), B lymphoma Mo-MLV insertion region 1 homolog (BMI1), Like Heterochromatin Protein 1 (LHP1) and Embryonic Flower 1 (EMF1) are the PRC1 core components and Vernalization 1 (VRN1), VP1/ABI3-Like 1/2/3 (VAL1/2/3), Alfin-like 1–7 (AL1–7), Inhibitor of growth 1/2 (ING1/2), and Early Bolting in Short Days (EBS) / Short Life (SHL) are the associated factors.

Results

Each PRC1 subunit possesses special domain organizations, such as RING and the ring finger and WD40-associated ubiquitin-like (RAWUL) domains for RING1 and BMI1, chromatin organization modifier (CHROMO) and chromo shadow (ChSh) domains for LHP1, one or two B3 DNA binding domain(s) for VRN1, B3 and zf-CW domains for VAL1/2/3, Alfin and Plant HomeoDomain (PHD) domains for AL1–7, ING and PHD domains for ING1/2, Bromoadjacent homology (BAT) and PHD domains for EBS/SHL. Six new motifs are uncovered in EMF1.

The PRC1 core components RING1 and BMI1, and the associated factors VAL1/2/3, AL1–7, ING1/2, and EBS/SHL exist from alga to higher plants, whereas LHP1 only occurs in higher plants. EMF1 and VRN1 are present only in eudicots. PRC1 components undergo duplication in the plant evolution. Most of plants carry the homologous core component LHP1, the associated factor EMF1, and several homologs in RING1, BMI1, VRN1, AL1–7, ING1/2/3, and EBS/SHL. Cabbage, cotton, poplar, orange and maize often exhibit more gene copies than other species. Domain organization analysis shows that duplicated gene functions may be of diverse.

Conclusions

The PRC1 core components RING1 and BMI1, and the associated factors VAL1/2/3, AL1–7, ING1/2, and EBS/SHL originate from algae. The core component LHP1 is from moss and the associated factors EMF1 and VRN1 are from dicotyledon. PRC1 components are of functional redundancy and diversity in evolution.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5905-9) contains supplementary material, which is available to authorized users.