Multi-omics analysis of response mechanism of programmed cell death in wheat endosperm to post-anthesis drought stress

Abstract

Post-anthesis drought stress (PADS) greatly influences wheat grain development and programmed cell death (PCD) in endosperm. However, the response mechanism of PCD in wheat endosperm to abiotic stress is still unclear at present. In this study, the physiological parameters and transcriptome and proteome of winter wheat varieties Xindong No. 18 (XD18, drought-sensitive variety) and Xindong No. 22 (XD22, drought-tolerant variety) under PADS were analyzed. The results showed that under PADS, the endosperm cell viability of XD18 and XD22 decreased, the number of nuclei with DNA break increased by 21% and 9%, respectively, the chromatin condensed, and the nuclear envelope rupture and cytoplasm leakage occurred, compared with those in the control group. Besides, the nuclei count of XD18 and XD22 decreased by 6.07% and 7.5%, respectively, and the DNA hydrolase activity (24.7% and 28.9%), H2O2 content (54.3% and 38.7%), and MDA content (44.1% and 33.8%) all increased. A total of 21,677 differentially expressed genes (DEGs) and 3388 differentially expressed proteins (DEPs) were detected. Among them, 48 PCD-related proteins were identified. The ubiquitin protein (TraesCS1A01G397400.1) exhibited a high expression level in XD22. The integrated transcriptomic and proteomic analysis showed that the expression of genes related to DNA repair and membrane functions were up-regulated, which confirmed the results of physiological analysis. Particularly, the glutathione-ascorbic acid cycle pathway and the mitogen-activated protein kinase (MAPK) signaling cascade pathway mediated by Ca2+, abscisic acid (ABA), ethylene (ETH), and flg22 were significantly enriched. Therefore, the two were key pathways involved in the regulation of wheat endosperm PCD under PADS. This study will deepen our understanding of the PCD in wheat endosperm in response to PADS, and is of great significance for screening candidate genes related to wheat stress resistance.