PeGRF6-PeGIF1 complex regulates cell proliferation in the leaf of Phalaenopsis equestris

An Ethyl Methanesulfonate-Induced GIF1 Splicing Site Mutation in Sesame Is Associated with Floral Malformation and Small Seed Size

Flower and inflorescence architecture play fundamental roles in crop seed formation and final yield. Sesame is an ancient oilseed crop. Exploring the genetic mechanisms of inflorescence architecture and developmental characteristics is necessary for high-yield breeding improvements for sesame and other crops. In this study, we performed a genetic analysis of the sesame mutant css1 with a malformed corolla and small seed size that was mutagenized by ethyl methanesulfonate (EMS) from the cultivar Yuzhi 11. Inheritance analysis of the cross derived from css1 mutant × Yuzhi 11 indicated that the mutant traits were controlled by a single recessive gene. Based on the genome resequencing of 48 F2 individuals and a genome-wide association study, we determined SNP9_15914090 with the lowest p value was associated with the split corolla and small seed size traits, which target gene Sigif1 (GRF-Interacting Factor 1). SiGIF1 contains four exons and encodes a coactivating transcription factor. Compared to the wild-type allelic gene SiGIF1, Sigif1 in the mutant css1 has a splice donor variant at the exon2 and intron2 junction, which results in incorrect transcript splicing with a 13 bp deletion in exon2. The expression profile indicated that SiGIF1 was highly expressed in the flower, ovary, and capsule but lowly expressed in the root, stem, and leaf tissues of the control. In summary, we identified a gene, SiGIF1, that regulates flower organs and seed size in sesame, which provides a molecular and genetic foundation for the high-yield breeding of sesame and other crops.

Genome-wide identification and expression profiling of growth‑regulating factor (GRF) and GRF‑interacting factor (GIF) gene families in chickpea and pigeonpea

The growth-regulating factor (GRF) and GRF-interacting factor (GIF) families encode plant-specific transcription factors and play vital roles in plant development and stress response processes. Although GRF and GIF genes have been identified in various plant species, there have been no reports of the analysis and identification of the GRF and GIF transcription factor families in chickpea (Cicer arietinum) and pigeonpea (Cajanus cajan). The present study identified seven CaGRFs, eleven CcGRFs, four CaGIFs, and four CcGIFs. The identified proteins were grouped into eight and three clades for GRFs and GIFs, respectively based on their phylogenetic relationships. A comprehensive in-silico analysis was performed to determine chromosomal location, sub-cellular localization, and types of regulatory elements present in the putative promoter region. Synteny analysis revealed that GRF and GIF genes showed diploid-polyploid topology in pigeonpea, but not in chickpea. Tissue-specific expression data at the vegetative and reproductive stages of the plant showed that GRFs and GIFs were strongly expressed in tissues like embryos, pods, and seeds, indicating that GRFs and GIFs play vital roles in plant growth and development. This research characterized GRF and GIF families and hints at their primary roles in the chickpea and pigeonpea growth and developmental process. Our findings provide potential gene resources and vital information on GRF and GIF gene families in chickpea and pigeonpea, which will help further understand the regulatory role of these gene families in plant growth and development.

Enhanced resistance to heat and fungal infection in transgenic Trichoderma via over-expressing the HSP70 gene

Heat stress is one of the major abiotic stresses affecting the growth, sporulation, colonization and survival of Trichoderma viride. This study aimed to gain a better insight into the underlying mechanism governing the heat stress response of T. viride Tv-1511. We analysed the transcriptomic changes of Tv-1511 under normal and heat stress conditions using RNA sequencing. We observed that Tv-1511 regulates the biosynthesis of secondary metabolites through a complex network of signalling pathways. Additionally, it significantly activates the anti-oxidant defence system, heat shock proteins and stress-response-related transcription factors in response to heat stress. TvHSP70 was identified as a key gene, and transgenic Tv-1511 overexpressing TvHSP70 (TvHSP70-OE) was generated. We conducted an integrated morphological, physiological and molecular analyses of the TvHSP70-OE and wild-type strains. We observed that TvHSP70 over-expression significantly triggered the growth, anti-oxidant capacity, anti-fungal activity and growth-promoting ability of Tv-1511. Regarding anti-oxidant capacity, TvHSP70 primarily up-regulated genes involved in enzymatic and non-enzymatic anti-oxidant systems. In terms of anti-fungal activity, TvHSP70 primarily activated genes involved in the synthesis of enediyne, anti-fungal and aminoglycoside antibiotics. This study provides a comparative analysis of the functional significance and molecular mechanisms of HSP70 in Trichoderma. These findings provide a valuable foundation for further analyses.

Plant non-coding RNAs: The new frontier for the regulation of plant development and adaptation to stress

Most plant transcriptomes constitute functional non-coding RNAs (ncRNAs) that lack the ability to encode proteins. In recent years, more research has demonstrated that ncRNAs play important regulatory roles in almost all plant biological processes by modulating gene expression. Thus, it is important to study the biogenesis and function of ncRNAs, particularly in plant growth and development and stress tolerance. In this review, we systematically explore the process of formation and regulatory mechanisms of ncRNAs, particularly those of microRNAs (miRNAs), small interfering RNAs (siRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Additionally, we provide a comprehensive overview of the recent advancements in ncRNAs research, including their regulation of plant growth and development (seed germination, root growth, leaf morphogenesis, floral development, and fruit and seed development) and responses to abiotic and biotic stress (drought, heat, cold, salinity, pathogens and insects). We also discuss research challenges and provide recommendations to advance the understanding of the roles of ncRNAs in agronomic applications.

Leaf growth - complex regulation of a seemingly simple process

Understanding the underlying mechanisms of plant development is crucial to successfully steer or manipulate plant growth in a targeted manner. Leaves, the primary sites of photosynthesis, are vital organs for many plant species, and leaf growth is controlled by a tight temporal and spatial regulatory network. In this review, we focus on the genetic networks governing leaf cell proliferation, one major contributor to final leaf size. First, we provide an overview of six regulator families of leaf growth in Arabidopsis: DA1, PEAPODs, KLU, GRFs, the SWI/SNF complexes, and DELLAs, together with their surrounding genetic networks. Next, we discuss their evolutionary conservation to highlight similarities and differences among species, because knowledge transfer between species remains a big challenge. Finally, we focus on the increase in knowledge of the interconnectedness between these genetic pathways, the function of the cell cycle machinery as their central convergence point, and other internal and environmental cues.