Transcription Analysis of Arabidopsis Membrane Transporters and Hormone Pathways during Developmental and Induced Leaf Senescence

Abstract

A comparative transcriptome analysis for successive stages of Arabidopsis (Arabidopsis thaliana) developmental leaf senescence (NS), darkening-induced senescence of individual leaves attached to the plant (DIS), and senescence in dark-incubated detached leaves (DET) revealed many novel senescence-associated genes with distinct expression profiles. The three senescence processes share a high number of regulated genes, although the overall number of regulated genes during DIS and DET is about 2 times lower than during NS. Consequently, the number of NS-specific genes is much higher than the number of DIS-or DET-specific genes. The expression profiles of transporters (TPs), receptor-like kinases, autophagy genes, and hormone pathways were analyzed in detail. The Arabidopsis TPs and other integral membrane proteins were systematically reclassified based on the Transporter Classification system. Coordinate activation or inactivation of several genes is observed in some TP families in all three or only in individual senescence types, indicating differences in the genetic programs for remobilization of catabolites. Characteristic senescence type-specific differences were also apparent in the expression profiles of (putative) signaling kinases. For eight hormones, the expression of biosynthesis, metabolism, signaling, and (partially) response genes was investigated. In most pathways, novel senescence-associated genes were identified. The expression profiles of hormone homeostasis and signaling genes reveal additional players in the senescence regulatory network.

ABA receptor PYL9 promotes drought resistance and leaf senescence

“…ABA accumulates in polar apical buds during short-day conditions, which may contribute to growth suppression and maintenance of dormancy (36). Of 146 BRC1-dependent bud dormancy genes that are putatively involved in shade-induced axillary bud dormancy, 78 are regulated during senescence (35,37,38). Strikingly, master positive regulators of senescence, such as ORE1, AtNAP, and MAX2/ORE9, are also upregulated during bud dormancy, suggesting that bud dormancy is coordinated with leaf senescence to contribute to stress resistance.…”

PvNAC1 and PvNAC2 Are Associated with Leaf Senescence and Nitrogen Use Efficiency in Switchgrass

“…S7 and 7d), which also occurs during natural and dark-induced senescence [13,15]. Remobilization of N compounds from leaves to other organs, mediated by GS1, GDH, and other enzymes, may explain the drop in N concentration in leaves expressing PvNACs (Figs.…”

“…Rice OsNAC5 was found to be induced earlier and to a greater extent in flag leaves and panicles of rice cultivars with higher seed protein content, indicating that OsNAC5 may be involved in amino acid remobilization from green tissues to seeds [12]. Although there have been some microarray-based transcriptomic studies of senescence in Arabidopsis [13][14][15], Populus [16], wheat [17], and barley [18], little is known about processes that are regulated directly by NAC TFs. Recently, the effect of downregulation of TtNAM-B1 on wheat flag-leaf gene expression during senescence (12 days after anthesis) was investigated using RNA-seq technology [19].…”

Overexpression of a LAM Domain Containing RNA-Binding Protein LARPIc Induces Precocious Leaf Senescence in Arabidopsis

“…Transcriptome analysis of senescent leaves indicated that approximately 2,500 genes (approximately 10%) in the Arabidopsis genome were expressed in senescent leaves (He et al, 2001). Microarray analysis showed that more than 800 SAGs were distinctively up-regulated during leaf senescence (Buchanan-Wollaston et al, 2005;Van Der Graaff et al, 2006). Post-transcriptional regulation plays an essential role in the regulation of gene expression during plant growth, development, and response to external stresses.…”

“…RNA-binding proteins are involved in multiple steps of post-transcriptional regulation, including pre-mRNA splicing, mRNA transport, localization, translation, and stability (Dreyfuss et al, 2002). Although many RNA-binding proteins are up-or down-regulated during leaf senescence, the biological functions of these genes are largely unknown (Buchanan-Wollaston et al, 2005;Van Der Graaff et al, 2006). Overexpression of three UBA2 genes (UBA2a, UBA2b, and UBA2c), which encode heterogeneous nuclear ribonucleoprotein (hnRNP)-type RNA-binding proteins, induce leaf senescence and hypersensitive-like cell death (Kim et al, 2008).…”