Characterization of a myrosinase cDNA from Brassica parachinensis and its defense role against Plutella xylostella after suppression

In Brassicaceae, myrosinase catalyzes the hydrolysis of glucosinolate and plays an important role in anti-herbivore defense. We have cloned and characterized the full- length complementary DNA of myrosinase gene from Brassicaparachinensis that exhibits high sequence identity with myrosinase genes from other Brassica species. To investigate the role of this myrosinase in defense against the diamondback moth （Plutella xylostella）, we constructed an RNA-interference （RNAi） cassette expressing a double-stranded RNA that targeted myrosinase and transfected it into B. parachinensis. Myrosinase was sup- pressed in the resulting transgenic plants. Diamondback moth larvae feeding on transgenic plants had lower larval and pupal weights, longer pupal duration, and lower fecundity than those feeding on non-transgenic plants, suggesting that the diamondback moth has adapted to the glucosinolate-myrosinase defensive system. Therefore, the suppression of myrosinase is a potential approach for controlling the diamondback moth.

菜心光敏色素B基因BcPHYB的鉴定与分析

菜心在长日照或短日照条件下均可抽薹开花,为解释菜心开花对光周期不敏感的分子机制,本研究以‘四九菜心’为材料,利用菜心叶片转录组测序数据鉴定了光敏色素B基因(BcPHYB)。通过构建系统树,发现菜心BcPHYB类似于早花大白菜BraPHYB2,并且在5’UTR中存在20 bp的InDel。菜心BcPHYB在pre-mRNA加工中存在着选择性剪接,一部分转录本会保留1号、2号或3号内含子,导致相应的BcPHYB蛋白产物中插入或者缺失部分氨基酸序列片段。本研究分析了菜心BcPHYB的InDel变异与选择性剪接情况,为阐释菜心对光周期不敏感的开花分子机制提供了帮助。