Construction of the Leaf Senescence Database and Functional Assessment of Senescence-Associated Genes.

Leaf senescence is the last phase of plant development and a highly coordinated process regulated by a large number of senescence-associated genes (SAGs). By broad literature survey, we constructed a leaf senescence database (LSD) in 2011 and updated it to Version 2.0 in 2014 ( http://www.eplantsenescence.org/ and http://psd.cbi.pku.edu.cn/ ) which contains a total of 5357 genes and 324 mutants from 44 species. These SAGs were retrieved based on genetic, genomic, proteomic, physiological, or other experimental evidence and were classified into different categories according to their functions in leaf senescence or morphological phenotype of mutants. To provide comprehensive information for SAGs, we made extensive annotation by both manual and computational approaches. In addition, we predicted putative orthologues of the SAGs in other species. LSD has a user-friendly interface to allow users to make text queries or BLAST searches and to download SAGs sequences for local analysis. Functional analyses of putative SAGs reveal that WRKY75, AZF2, NAC16, and WRKY26 are positive regulators of leaf senescence, while MKP2 and CTR1 perform negative regulation to leaf senescence. This database has been served as a valuable resource for basic research on the function of SAGs and evolution of plant leaf senescence, as well as for the exploration of genetic traits in agronomically important plants.