Gene coexpression network analysis reveals the role of SRS genes in senescence leaf of maize (Zea mays L.)

Shi-related sequence (SRS) proteins are plant-specific transcription factors that play important roles in developmental processes, including regulating hormone biosynthesis, response or signal transduction. However, systematical analysis of the SRS gene family in maize has not yet been conducted. In this study, 11 SRS genes with 13 transcripts were identified and characterized. The characteristics of the gene family were analysed in terms of phylogenetic relationships, chromosome distribution and gene structure. RNA-sequencing data analysis showed that the expression patterns of SRS genes were quite different from each other in maize, indicating their divergence in function. Interestingly, the GRMZM2G077752 gene is highly expressed in senescent leaves. Using further coexpression network analysis, we determined that the module containing GRMZM2G077752 were over-represented by genes related to abscisic acid (ABA) stimulus and carbohydrate metabolic process. This result indicated that GRMZM2G077752 might perceive ABA signal and cause the activation of carbohydrate remobilization during leaf ageing. This study provides valuable information for understanding the functions of the SRS genes in maize.

Gene coexpression analysis reveals dose-dependent and type-specific networks responding to ionizing radiation in the aquatic model plant Lemna minor using public data

Ionizing radiations (IRs) are widespread damaging stresses to plant growth and development. However, the regulatory networks underlying the mechanisms of responses to IRs remains poorly understood. Here, a set of publicly available transcriptomic data (conducted by Van Hoeck et al. 2015a), in which Lemna minor plants were exposed to a series of doses of gamma, beta and uranium treatments was used to perform gene coexpression network analysis. Overall, the genes involved in DNA synthesis and chromatin structure, light signalling, photosynthesis, and carbohydrate metabolism were commonly responsive to gamma, beta and uranium treatments. Genes related to anthocyanin accumulation and trichome differentiation were specifically downregulated, andgenes related to nitrogen and phosphate nutrition, cell vesicle transport, mitochondrial electron transport and ATP synthesis were specifically upregulated in response to uranium treatment. While genes involved in DNA damage and repair, RNA processing and RNA binding were specifically downregulated and genes involved in calcium signalling, redox and degradation of carbohydrate metabolism were specifically upregulated responding to gamma radiation. These findings revealed both dose-dependent and typespecific networks responding to different IRs in L. minor, and can be served as a useful resource to better understand the mechanisms of responses to different IRs in other plants.