Histone acetyltransferase HAM1 interacts with molecular chaperone DNAJA2 and confers immune responses through salicylic acid biosynthetic genes in cassava

Genome-wide analysis of apple histone acetyltransferases reveals the regulatory roles of MdHAG1 and MdHAM1 in response to abiotic stresses

It is known that histone acetyltransferases (HATs) are involved in a wide range of biological processes by activating gene expression. However, the regulatory role of HATs in apple remains to be elucidated. This study identified 58 HATs from the apple genome (named MdHATs) and performed comprehensive analyses of these MdHATs, given their involvements in plant development and stress response. Firstly, we classified 58 predicted MdHATs into four different categories based on the phylogenetic analyses. Then, the intron/exon structures, conserved motifs, and structural domain organization of MdHAT genes and predicted proteins were further analyzed. Next, we investigated the expression patterns of MdHATs during apple plants' development process and stress responses. Moreover, according to these findings, we selected two candidate genes, MdHAG1 and MdHAM1, and ectopically expressed them in tobacco to investigate their function in response to drought and low-temperature stress, respectively. The results showed that overexpression of MdHAG1 in tobacco negatively regulated drought tolerance and cold tolerance of transgenic tobacco, and overexpression of MdHAM1 in tobacco improved drought tolerance and cold tolerance of transgenic tobacco. In summary, our study provides a comprehensive analysis of the MdHAT family and insights into the epigenetic mechanisms of histone acetylases under abiotic stress.

Overexpression of FvGCN5 enhances the resistance of woodland strawberry against Botrytis cinerea

Epigenetic modifications mediated by histone acetylation play essential roles in plant development and stress response. However, the mechanism of regulating biotic stress through histone acetyltransferase GCN5 in strawberry is still unclear. In this study, we isolated FvGCN5 from woodland strawberry and found that FvGCN5 may form the conserved SAGA (Spt-Ada-Gcn5 acetyltransferase) complex through interaction with FvADA2a and FvADA2b. In addition, we found that FvGCN5 could be significantly induced by the infection of fungal pathogen Botrytis cinerea, and that the transgenic strawberry plants overexpressing FvGCN5 exhibited enhanced resistance against B. cinerea. Further RNA-seq-based transcriptome and quantitative PCR analysis indicated that several disease-resistant genes such as FvMYC2 and, FvPR1 were significantly upregulated in FvGCN5 overexpression lines. Taken together, our study indicates that FvGCN5 plays important roles in the resistance against B. cinerea in woodland strawberry through activating disease-resistant genes.

CitGATA7 interact with histone acetyltransferase CitHAG28 to promote citric acid degradation by regulating the glutamine synthetase pathway in citrus

Organic acid is a crucial indicator of fruit quality traits. Citric acid, the predominant organic acid in citrus fruit, directly influences its edible quality and economic value. While the transcriptional regulatory mechanisms of citric acid metabolism have been extensively studied, the understanding about the transcriptional and epigenetic co-regulation mechanisms is limited. This study characterized a transcription factor, CitGATA7, which directly binds to and activates the expression of genes associated with the glutamine synthetase pathway regulating citric acid degradation. These genes include the aconitase encoding gene CitACO3, the isocitrate dehydrogenase encoding gene CitIDH1, and the glutamine synthetase encoding gene CitGS1. Furthermore, CitGATA7 physically interacts with the histone acetyltransferase CitHAG28 to enhance histone 3 acetylation levels near the transcription start site of CitACO3, CitIDH1, and CitGS1, thereby increasing their transcription and promoting citric acid degradation. The findings demonstrate that the CitGATA7-CitHAG28 protein complex transcriptionally regulate the expression of the GS pathway genes, i.e., CitACO3, CitIDH1, and CitGS1, via histone acetylation, thus promoting citric acid catabolism. This study establishes a direct link between transcriptional regulation and histone acetylation regarding citric acid metabolism, providing insights for strategies to manipulate organic acid accumulation in fruit.

Research Progress on the Mechanism and Function of Histone Acetylation Regulating the Interaction between Pathogenic Fungi and Plant Hosts

Histone acetylation is a crucial epigenetic modification, one that holds the key to regulating gene expression by meticulously modulating the conformation of chromatin. Most histone acetylation enzymes (HATs) and deacetylation enzymes (HDACs) in fungi were originally discovered in yeast. The functions and mechanisms of HATs and HDACs in yeast that have been documented offer us an excellent entry point for gaining insights into these two types of enzymes. In the interaction between plants and pathogenic fungi, histone acetylation assumes a critical role, governing fungal pathogenicity and plant immunity. This review paper delves deep into the recent advancements in understanding how histone acetylation shapes the interaction between plants and fungi. It explores how this epigenetic modification influences the intricate balance of power between these two kingdoms of life, highlighting the intricate network of interactions and the subtle shifts in these interactions that can lead to either mutual coexistence or hostile confrontation.

Plant responses to abiotic stress regulated by histone acetylation

In eukaryotes, histone acetylation and deacetylation play an important role in the regulation of gene expression. Histone acetylation levels are reversibly regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Increasing evidence highlights histone acetylation plays essential roles in the regulation of gene expression in plant response to environmental stress. In this review, we discussed the recent advance of histone acetylation in the regulation of abiotic stress responses including temperature, light, salt and drought stress. This information will contribute to our understanding of how plants adapt to environmental changes. As the mechanisms of epigenetic regulation are conserved in many plants, research in this field has potential applications in improvement of agricultural productivity.

Recent advancements in the role of histone acetylation dynamics to improve stress responses in plants

In eukaryotes, transcriptional regulation is determined by the DNA sequence and is facilitated through sophisticated and complex chromatin alterations and histone remodelling. Recent research has shown that the histone acetylation dynamic, an intermittent and reversible substitution, constitutes a prerequisite for chromatin modification. These changes in chromatin structure modulate genome-wide and specific changes in response to external and internal cues like cell differentiation, development, growth, light temperature, and biotic stresses. Histone acetylation dynamics also control the cell cycle. HATs and HDACs play a critical role in gene expression modulation during plant growth and response to environmental circumstances. It has been well established that HATs and HDACs interact with various distinct transcription factors and chromatin-remodelling proteins (CRPs) involved in the transcriptional regulation of several developmental processes. This review explores recent research on histone acyltransferases and histone deacetylases, mainly focusing on their involvement in plant biotic stress responses. Moreover, we also emphasized the research gaps that must be filled to fully understand the complete function of histone acetylation dynamics during biotic stress responses in plants. A thorough understanding of histone acetylation will make it possible to enhance tolerance against various kinds of stress and decrease yield losses in many crops.

Coat protein of cassava common mosaic virus targets RAV1 and RAV2 transcription factors to subvert immunity in cassava

Cassava common mosaic virus (CsCMV, genus Potexvirus) is a prevalent virus associated with cassava mosaic disease, so it is essential to elucidate the underlying molecular mechanisms of the coevolutionary arms race between viral pathogenesis and the cassava (Manihot esculenta Crantz) defense response. However, the molecular mechanism underlying CsCMV infection is largely unclear. Here, we revealed that coat protein (CP) acts as a major pathogenicity determinant of CsCMV via a mutant infectious clone. Moreover, we identified the target proteins of CP-related to abscisic acid insensitive3 (ABI3)/viviparous1 (VP1) (MeRAV1) and MeRAV2 transcription factors, which positively regulated disease resistance against CsCMV via transcriptional activation of melatonin biosynthetic genes (tryptophan decarboxylase 2 (MeTDC2), tryptamine 5-hydroxylase (MeT5H), N-aceylserotonin O-methyltransferase 1 (MeASMT1)) and MeCatalase6 (MeCAT6) and MeCAT7. Notably, the interaction between CP, MeRAV1, and MeRAV2 interfered with the protein phosphorylation of MeRAV1 and MeRAV2 individually at Ser45 and Ser44 by the protein kinase, thereby weakening the transcriptional activation activity of MeRAV1 and MeRAV2 on melatonin biosynthetic genes, MeCAT6 and MeCAT7 dependent on the protein phosphorylation of MeRAV1 and MeRAV2. Taken together, the identification of the CP-MeRAV1 and CP-MeRAV2 interaction module not only illustrates a molecular mechanism by which CsCMV orchestrates the host defense system to benefit its infection and development but also provides a gene network with potential value for the genetic improvement of cassava disease resistance.