Multiple functions of Jasmonate ZIM domain (JAZ) proteins in N. attenuata plants : growth, development, and defense against herbivores

Oh, Youngjoo

The Jasmonate-ZIM domain (JAZ) proteins are key repressor of jasmonic acid (JA) signaling in plant. I identified 12 novel JAZ proteins in the native tobacco Nicotiana attenuata The NaJAZ genes showed spatially and temporally different expression patterns after simulated herbivory. N. attenuata plants silenced in the expression of either NaJAZd or NaJAZh by RNAi-mediated gene silencing were used to characterize their individual functions. NaJAZh negatively regulates a subset of direct defenses (TPIs and 17-HGT-DTGs) and indirect defenses (VOCs) in N. attenuata and affects the performance of the specialist herbivore Manduca sexta. Interestingly, NaJAZh positively regulates nicotine accumulation in leaves, which could be explained by a crosstalk of JAZ genes: NaJAZh silencing up-regulated several other JAZ genes such as NaJAZf, NaJAZj, and NaJAZb. NaJAZh is also required to repress programmed cell death in the leaves by regulating ROS level (e.g. H2O2). In contrast NaJAZh, NaJAZd plays only a minor role in defense, but plays an important role in flower development. NaJAZd silencing strongly affected the lifetime production of seed capsules compared to WT plants, by causing enhanced flower abscission which is resembled the phenotype of NaMYB305-silenced plants. NaMYB305 plays a major role in flower opening and its silencing caused premature flower abscission in N. attenuata. Notably, NaJAZd-silenced flowers had altered transcript abundance of NaMYB305 at the open flower stage. In addition NaJAZd-silenced flowers showed significantly repressed levels of JA and JA-Ile. I proposed that NaJAZd counteracts flower abscission by regulating JA, JA-Ile levels and/or expression of NaMYB305 in N. attenuata, permitting seed production in plants. Here, I show a single JAZ protein can control specific jasmonate-dependent defenses and developmental processes, which strongly supports the hypothesis that JAZ proteins are functionally specialized in both defense and development

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Oh, Youngjoo: Multiple functions of Jasmonate ZIM domain (JAZ) proteins in N. attenuata plants. growth, development, and defense against herbivores. 2013.

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