关键词: 印度酸橘, 柠檬, CrNCED1, 脱水, 非生物胁迫, 脱落酸, 功能分析

Abstract: To explore the function of CrNCED1，a key enzyme gene during abscisic acid biosynthesis in Cleopatra Mandarin（Citrus reshni），the expression characteristics of CrNCED1 was analyzed. Transgenic plants were obtained by overexpression of CrNCED1 in lemon for assaying dehydration resistance. The results showed that CrNCED1 showed the highest expression levels in leaves of Citrus reshni. Transcript levels of CrNCED1 were induced by dehydration，low temperature and ABA，but not by salt stress，among which ABA treatment strongly induced the expression of CrNCED1. The ABA content of transgenic lemon plants overexpressing CrNCED1 was remarkably higher than that of wild type. Upon exposure to dehydration treatment，the transgenic lines displayed less severe leaf wilting degree，concurrent with noticeably lower relative water loss，MDA and reactive oxygen species contents，and substantially smaller stomatal aperture in comparison with the wild type，indicating that overexpression of CrNCED1 conferred enhanced dehydration resistance in transgenic lemon plants.

Key words: Citrus reshni, lemon, CrNCED1, dehydration, abiotic stress, abscisic acid, functional analysis