Dr. Shuxun Yu, Dr. Meizhen Song, and Dr. Shuli Fan. Cotton Research Institute, CAAS, Key Laboratory of Cotton Genetic Improvement ministry of AgricuIture, China, yellow river road,development district, anyang, henan, China
The study was to investigate the genetic basis of biochemical traits associated with the antioxidant system and phytohormones, and cloning of senescence-related genes. Two types of short season cotton, Gossypium hirsutum, cultivars were used in the experiments: five premature senescence cultivars(Group A) and five early maturing cultivars without premature senescence(Group B). A cysteine proteinase gene from cotton was isolated by rapid amplification of cDNA ends using polymerase chain reaction (RACE-PCR). CAT, SOD, and POD were higher in the B Group compared with the A Group, whereas the MDA was lower in Group B. Various genetic variances and heritability for these biochemical traits and IAA, ABA, and chlorophyll contents were estimated. The expression of the Ghcysp gene in young leaves is insensitive to ABA, H2O2, and darkness, which have been reported to accelerate leaves senescence. The short season cotton cultivars without premature senescence have higher yield and good quality. The Ghcysp gene is a developmentally regulated, senescence-specific gene. Its expression only occurs during the senescence of the older leaves.
