以玉米基础自交系(AS-9)及其化学诱变自交系M4为实验材料进行耐盐性鉴定,同时利用44对可能与根系性状有关联的SSR引物进行遗传变异分析。结果表明,诱变M4幼苗经200和250 mmol·L-1 Na Cl盐胁迫处理7 d后,IV400、IV1600根数比AS-9对照分别增加23.1%、19.1%,诱变IV1600初生根1、2、3根长分别为对照的1.33、1.70、2.15倍;同时在M4玉米试材中扩增出多态性条带的引物25对,占引物总数的56.82%;诱变自交系M4与AS-9的遗传相似系数平均值为0.6563,遗传相似系数中心化后,数据在-0.04处可把材料分为三个类群,基础材料AS-9为Ⅰ类,M4代IV1400、IV1600、IV2000聚为Ⅲ类,其余诱变系为Ⅱ类。此外,6对引物的SSR-PCR产物进行序列差异检测,结果产生新的基元和基元重复次数变化,说明系列化学诱变已使玉米自交系AS-9产生了显著的遗传变异。
旨在筛选高山植物喜马拉雅紫茉莉调控类黄酮等次生代谢产物合成的MYB转录因子(MhMYB)基因家族。基于喜马拉雅紫茉莉愈伤组织低温转录组测序数据库,利用PlantTFDB 3.0和BLASTP等软件对MhMYB序列进行筛选与鉴定,使用Web Logo 3.0、MEGA 7.0和Mev等生物信息学软件对MhMYB转录因子进行结构域、系统进化及低温诱导表达水平分析。研究筛选出34个喜马拉雅紫茉莉MhMYB家族成员,分别为1R-MYB(2个)、R2R3-MYB(30个)和3R-MYB(2个)3类转录因子;亚细胞定位预测大多数定位于细胞核中;进化分析显示,MhMYB家族成员可分为15个亚类,基于拟南芥AtMYB家族成员的生物学功能,预测MhMYB的S2、S7、S20亚家族成员可能参与调控类黄酮等次生代谢产物合成;转录组数据分析显示,低温可诱导MhMYB6、MhMYB15、MhMYB62基因表达水平增加;共表达分析发现,MhMYB6、MhMYB15、MhMYB62对类黄酮合成途径基因起到一定调控作用。初步研究表明,MhMYB6、MhMYB15、MhMYB62可参与调控低温诱导喜马拉雅紫茉莉类黄酮的累积。
Aim Mirabilis himalaica(Nyctaginaceae)is an endangered medicinal plant mainly distributed in the plateau region of northern Tibet,China.The outer surface of M.himalaica achenes is covered by a pectinaceous mucilaginous layer upon hydration.However,the role of the achene mucilage is poorly understood.in this study,we inves-tigated the effects of mucilage on achene germination and sprout growth under abiotic stress to explain how M.himalaica survive the alpine environment.Methods We investigated the effect of mucilage on achenes germination by contrast the capacity of water absorption,dehydration and respira-tion of intact achene and the achene with mucilage removal.We performed abiotic stresses experiments including drought stress,salt stress,cold stress and high temperature stress,and quantified the effects of mucilage removal on achene germination rate,root and shoot lengths of seedlings.Important Findings Mucilage is extremely hydrophilic,and the mass of intact achenes can be 9-fold greater than that of demucilaged achenes.The removal of the mucilaginous layer did not significantly change final germination percentages under ideal conditions,but intact achenes(i.e.with muci-lage)took longer to germinate.The mucilage significantly decreased seed respiration rates by acting as a physical barrier that prevented oxygen diffusion.Germination rates,shoot and root growth of intact achenes were higher than those of demucilaged ones during exposures to cold,heat,osmotic and salt stresses.Achene mucilage presumably plays an ecologically important role in the life cycle of M.himalaica by aiding the critical achene germination and early seedling growth in the stressful habitats of the plateau region of northern Tibet.
Yuzhen ChenLu ZhangXiao LuXiaozhong LanMan ShenCunfu Lu
