Up-regulation of autophagy by low concentration of salicylic acid delays methyl jasmonate-induced leaf senescence

Abstract

15Crosstalk between salicylic acid (SA) and jasmonic acid (JA) signaling plays an important 16 role in molecular regulation of plant senescence. Our previous works found that SA could 17 delay methyl jasmonate (MeJA)-induced leaf senescence in a concentration-dependent 18 manner. Here, the effect of low concentration of SA (LCSA) application on MeJA-induced 19 leaf senescence was further assessed. High-throughput sequencing (RNA-Seq) results 20 showed that LCSA did not have dominant effects on the genetic regulatory pathways of 21 basal metabolism like nitrogen metabolism, photosynthesis and glycolysis. The 22ClusterONE was applied to identify discrete gene modules based on protein-protein 23 interaction (PPI) network. Interestingly, an autophagy-related (ATG) module was identified 24 in the differentially expressed genes (DEGs) that exclusively induced by MeJA together 25 with LCSA. RT-qPCR confirmed that the expression of most of the determined ATG genes 26 were upregulated by LCSA. Remarkably, in contrast to wild type (Col-0), LCSA cannot 27 alleviate the leaf yellowing phenotype in autophagy defective mutants (atg5-1 and atg7-2) 28 upon MeJA treatment. Confocal and western blot results showed that LCSA increased the 29 number of autophagic bodies and autophagic flux during MeJA-induced leaf senescence. 30 Collectively, our work revealed up-regulation of autophagy by LCSA as a key regulator to 31 alleviate MeJA-induced leaf senescence. 32 salicylic acid 34 35 RNA-Seq analysis 132 Detached 3rd and 4th rosette leaves from 4-week old plants were immersed in 3 mM MES 133 buffer (pH 5.8) containing 10 μM SA, 50 μM MeJA, and MeJA together with SA for 24 h. 134Total RNA for RNA-Seq was extracted from leaves using a Hipure plant RNA kit (Magen, 135

Stem girdling affects the onset of autumn senescence in aspen in interaction with metabolic signals

“…A group of metabolites that separated stand 1 from the others was phenolic acids: salicylic acid, benzoic acid, and caffeic acid that increased in response to girdling in stand 1 and decreased in the other stands (Figure 7C) indicating that salicylic acid may be involved in the regulation of senescence in aspen. One possible explanation is that elevated salicylic acid levels may avert girdling‐induced senescence in stand 1 due to its antagonistic effect on the jasmonate signaling pathway (Miao & Zentgraf, 2007; Van der Does et al, 2013; Yin et al, 2020), that could be activated by girdling, based on the enhanced expression of PR3 ( PATHOGENESIS RELATED PROTEIN 3 , Potra001809g14625, log 2 fc 3.88) and repressed expression of JAZ8 ( JASMONATE‐ZIM‐DOMAIN PROTEIN 8 , Potra004547g25056, log 2 fc − 1.51), a repressor of jasmonic acid signaling (Table S1).…”

“…One possible explanation is that elevated salicylic acid levels may avert girdling-induced senescence in stand 1 due to its antagonistic effect on the jasmonate signaling pathway (Miao & Zentgraf, 2007; Van der Does et al, 2013;Yin et al, 2020), that could be activated by S1).…”

Leaf senescence: progression, regulation, and application

“…The studies on SA dihydroxylases, SA 3-HYDROXYLASE (S3H) and S5H, showed that SA is involved in both the onset and the progression of leaf senescence (Zhang et al 2013(Zhang et al , 2017b. In addition, SA has been shown to promote leaf senescence by inducing autophagic lysosome formation (Yoshimoto et al 2009;Xiao et al 2010;Yin et al 2020). It is well recognized that SA plays a direct role in both the onset and progression of leaf senescence, but most of these results are from Arabidopsis studies.…”

Systematic prediction of autophagy‐related proteins using Arabidopsis thaliana interactome data

“…In the senescence stage, leaves degenerate and rearrange nutrients accumulated during the growth stage to sink parts such as seeds, assisting the plant in productivity and fitness. Protein autophagy plays a central role in leaf senescence (Yin et al ., 2020). Here, using the RNA‐Sequencing data (http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE43616) (Woo et al ., 2016) from GEO (Edgar et al ., 2002) for the entire lifespan of Arabidopsis leaves, we explored how the genes encoding ARMs are regulated during the senescence stage, which to a large extent reflects the process of protein autophagy.…”