Identification of senescence-related genes by cDNA-AFLP in cotton (Gossypium hirsutum L.)

Abstract

Premature senescence at the late developmental stage occurs frequently in cotton (Gossypium hirsutum L.) production in North China. It is desirable to develop elite cotton cultivars with non-premature senescence and high photosynthetic capacity. In this study, cDNAamplified fragment length polymorphism (cDNA-AFLP) analysis was employed to identify the genes that are related to senescence in cotton. Using 64 primer combinations, about 3000 cDNA fragments were generated, and among them 42 had a markedly up-regulated expression pattern with the leaf growth progression. Based on cloning, sequencing, and Blast search analysis, it was determined that 24 TDFs with putative known biologic functions could be classified into several major categories, such as signal transduction, transcription regulation, stress-responsive, primary and secondary metabolism, nutrients recycling, photosynthesis, cell wall biosynthesis, and senescencerelated. TDF31, TDF32 and TDF33, with high similarity to the senescent-regulating genes MAP kinase 9 (MKK9) and non-yellowing protein 1(NYE1) from Arabidopsis and bean senescence-associated receptor-like kinase (SARK) could play possible roles in responding or modulating the leaf senescence in cotton. Therefore, leaf senescence in cotton is a complicated network involving many biological processes. Some putative genes with important modulation functions in regulating or responding to the senescence need to be further analyzed.