Api 8 13:30 An emerging integrated model for controlling longevity of leaves and fruits

Speaker：Susheng Gan

Host：Ling Xu
When：2014-4-8  13:30
Where：Conference Room 534, School of Life Sciences

Abstract：Leaf/fruit senescence is a genetically fine-tuned program that involves thousands of genes encoding, for examples, various transcription factors and components of signal transduction pathways. The cell attrition and nutrient recycling processes can be induced and regulated by various environmental cues and endogenous plant hormones [1]. We have identified a NAC transcription factor gene named AtNAP that plays a key role in leaf senescence. Knocking-out and inducible gain-of-function render significantly delayed or precocious leaf senescence, respectively [2]. This is achieved by activating its target genes, including (i) SAG113 protein phosphatase 2C gene that mediates abscisic acid or ABA’s unusual role in preventing stomatal closure at the onset of and during leaf senescence [3,4]; (ii) SAG202 transcrition factor gene that is involved in biosynthesis of salicylic acid (SA), which in turn activates an SA 3-hydroxylase gene to prevent overaccumulation of SA [5]; and (iii) SAG203 that is to inactivate the senescence-inhibition hormone cytokinins. The AtNAP-based regulatory network involving phosphorelay and plant hormones ABA, SA and cytokinins will be presented.

1. Gan S-S (2010) The hormonal regulation of senescence. In: Davies PJ, editor. Plant Hormones: Biosynthesis, Signal Transduction, Action! Revised 3rd Edition ed. New York: Springer. pp. 597-617.

2. Guo Y, Gan S-S (2006) AtNAP, a NAC family transcription factor, has an important role in leaf senescence. Plant J 46: 601-612.

3. Zhang K, Gan S-S (2012) An abscisic acid-AtNAP transcription factor-SAG113 protein phosphatase 2C regulatory chain for controlling dehydration in senescing Arabidopsis leaves. Plant Physiol 158: 961–969.

4. Zhang K, Xia X, Zhang Y, Gan S-S (2012) An ABA-regulated and Golgi-localized protein phosphatase controls water loss during leaf senescence in Arabidopsis. Plant J 69: 667-678.

5. Zhang K, Halitschke R, Yin C, Liu C-J, Gan S-S (2013) Salicylic acid 3-hydroxylase regulates Arabidopsis leaf longevity by mediating salicylic acid catabolism. Proc Natl Acad Sci USA 110 14807–14812.