Characterization and Fine Mapping of a Necrotic Leaf Mutant in Maize.pdf

Available online at Journal of Genetics and Genomics 40 (2013) 307e314 JGG ORIGINAL RESEARCHCharacterization and Fine Mapping of a Necrotic Leaf Mutant in Maize (Zea mays L.) Lijing Wang1, Shuai Han1, Shiyi Zhong, Haizhong Wei, Yanjun Zhang, Yan Zhao, Baoshen Liu* College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, China Received 24 December 2012; revised 1 April 2013; accepted 7 April 2013 Available online 20 April 2013ABSTRACT Maize (Zea mays L.) is a commercially important crop. Its yield can be reduced by mutations in biosynthetic and degradative pathways that cause death. In this paper, we describe the necrotic leaf (nec-t) mutant, which was obtained from an inbred line, 81647. The nec-t mutant plants had yellow leaves with necrotic spots, reduced chlorophyll content, and the etiolated seedlings died under normal growth conditions. Transmission electron microscopy revealed scattered thylakoids, and reduced numbers of grana lamellae and chloroplasts per cell. Histochemical staining suggested that spot formation of nec-t leaves might be due to cell death. Genetic analysis showed that necrosis was caused by the mutation of a recessive locus. Using simple sequence repeat markers, the Nec-t gene was mapped between mmc0111 and bnlg2277 on the short arm of chromosome 2. A total of 1287 individuals with the mutant phenotype from a F2 population were used for physical mapping. The Nec-t gene was located between markers T31 and H8 within a physical region of 131.7 kb. KEYWORDS: Maize (Zea mays L.); Necrosis; Molecular marker; Gene mappingINTRODUCTION A plant is affected by many kinds of stresses in its life, such as water, temperature, light, soil, and microbes. These stresses can result in various types of physiological damage. Plants resist such stresses by making metabolic and structural ad- justments. If a defect exists in such processes, lesions and necrosis or even programmed cell death (PCD) may result. PCD ha