Transcriptome Analysis of a Premature Leaf Senescence Mutant of Common Wheat (Triticum aestivum L.)

Abstract

Leaf senescence is an important agronomic trait that affects both crop yield and quality. In this study, we characterized a premature leaf senescence mutant of wheat (Triticum aestivum L.) obtained by ethylmethane sulfonate (EMS) mutagenesis, named m68. Genetic analysis showed that the leaf senescence phenotype of m68 is controlled by a single recessive nuclear gene. We compared the transcriptome of wheat leaves between the wild type (WT) and the m68 mutant at four time points. Differentially expressed gene (DEG) analysis revealed many genes that were closely related to senescence genes. Gene Ontology (GO) enrichment analysis suggested that transcription factors and protein transport genes might function in the beginning of leaf senescence, while genes that were associated with chlorophyll and carbon metabolism might function in the later stage. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the genes that are involved in plant hormone signal transduction were significantly enriched. Through expression pattern clustering of DEGs, we identified 1012 genes that were induced during senescence, and we found that the WRKY family and zinc finger transcription factors might be more important than other transcription factors in the early stage of leaf senescence. These results will not only support further gene cloning and functional analysis of m68, but also facilitate the study of leaf senescence in wheat.

Transcriptome Analysis of Gene Expression Patterns Potentially Associated with Premature Senescence in Nicotiana tabacum L.

“…Also, except for the regulation of metabolic and biosynthetic process, regulation of cellular component synthesis accounted for a large proportion, speculating possible patterns in premature senescence. Focusing on the KEGG results, many of the 15 pathways were verified to be associated with senescence by previous reports, for example, circadian rhythm-plant and tyrosine metabolism were enriched in senescent sorghum [ 47 ], alpha-linolenic acid metabolism existed in Arabidopsis [ 63 ], and premature-senescent wheat mutant [ 64 ], which showed that the senescence or premature senescence was partly the same and partly distinctive.…”

Identification of transcription factors regulating senescence in wheat through gene regulatory network modelling

“…Over 50 % of micro and macronutrients remobilised to the developing 56 grain originate from the uppermost (flag) leaf of the senescing wheat plant (Garnett and Graham,57 2005; Kichey et al, 2007), making it a key tissue in which to understand the senescence process. 58 Previous attempts have been made to characterise transcriptional changes in wheat flag leaves, 59 however these studies have been either carried out with microarrays which were limited to a small 60 set of 9,000 genes (Gregersen and Holm, 2007) or had a limited number of samples and time points 61 (Pearce et al, 2014;Zhang et al, 2018). Decreases in the cost of RNA-Seq now mean that these 62 constraints can be overcome through genome-wide expression studies across multiple time points.…”

Identification of Transcription Factors Regulating Senescence in Wheat through Gene Regulatory Network Modelling

“…Over 50% of micro-and macronutrients remobilized to the developing grain originate from the uppermost (flag) leaf of the senescing wheat plant (Garnett and Graham, 2005;Kichey et al, 2007), making it a key tissue in which to understand the senescence process. Previous attempts have been made to characterize transcriptional changes in wheat flag leaves; however, these studies have been either carried out with microarrays, which were limited to a small set of 9,000 genes (Gregersen and Holm, 2007), or had a limited number of samples and time points (Pearce et al, 2014;Zhang et al, 2018). Decreases in the cost of RNA sequencing (RNA-Seq) now mean that these constraints can be overcome through genome-wide expression studies across multiple time points.…”