蓖麻毒蛋白前体基因的时空表达模式分析

摘要

蓖麻毒蛋白（Ricin）是一类异二聚体复合物，包括一条具有催化活性的A链和具有半乳糖识别功能的B链，具有剧毒性。以RC2蓖麻为材料，利用半定量PCR和定量PCR技术分析蓖麻毒蛋白前体基因的时空表达模式。结果表明，在苗期蓖麻各组织中蓖麻毒蛋白前体基因不表达，而在成熟开花植株的各组织部位中，只在根和种子中有表达；而在种子发育过程中，授粉后1～2d内，子房中蓖麻毒蛋白前体基因有表达，之后伴随种子生长发育特异性表达消失；授粉后24 d，蓖麻毒蛋白前体基因再次表达，并且表达量快速增高。这一规律的发现为进一步研究蓖麻毒蛋白合成积累以及选育低毒蓖麻提供了重要参考。%RICIN,a heterodimeric complex with hypertoxicity,is composed of one bind of A-chain with catalytic activity and one bind of B-chain with recognition function for galactose.In this paper,the temporal and spatial expression patterns of RICIN precursor gene in Ricunus communis was analyzed by semi-quantitative RT-PCR and real-time quantitative PCR with caster RC2 as material.The results showed that the RICIN precursor gene did not express in any tissues at seed-ling stage,and only in the roots and seeds at the flowering stage.During the seed developing progress,the RICIN precursor gene expressed in ovaries within 1 ~2 days after pollination (DAP ),and then silenced with the development of seeds.While on 24 DAP,the RICIN precursor gene re-expressed and the expression level was rapidly increased.This dis-covery provides important references for further research on synthesis and accumulation of RICIN and breeding of low-tox-icity caster strains.