| Carotenoids are a group of important natural pigments.They are not only precursors of phytohormone(ABA BLs et al),but also playing important roles in light harvesting and photoprotection,therefore they are important for the development of plants.Humans and animals can’t produce carotenoids independently,they have to take it from food and produce necessary material using them.Research on carotenoid biosynthetic pathway has huge significance on improving human beings’ health,it has become a hotspot home and abroad.The research of this pathway is forcus on carotenoid biosynthetic pathway and function of key enzymes,however,the regulation mechanism and influence mechanism are not clear recently.ZISO gene encodes15-cis-ζ-carotene isomerase which is an important isomerase of carotenoid biosynthetic pathway,this isomerization can also be mediated by light.The isomerization can be in rails without ZISO in light,therefore the biological functions of ZISO still have a debate.In this study,we used the mutants of ZISO to explore the ZISO biological functions in different light conditions.From our study,we found the mutants have the phenotype of yellowing euphylla 、 short individual、delaying development,while several lines of ZISO overexpression transgenic plants have the phenotypes of yellow leaves、short root、small individual.Furthermore,we found that ZISO is a plastid–localized protein and ZISO express level is very high in the position having vigorous life(leave 、flower 、developing capsule et al.),ZISO also expresses in cotyledon 、hypocotyl 、 root of etiolated seedings growing in dark.ZISO may participates in photomorphogenesis,ZISO mutants have higher photosensitivity,and the lose of carotenoids can restrain the growth of the root.The mutation of ZISO can influence photoprotection,the ZISO mutants shown yellow leaves under strong light condition,but this phenotype disappear after reducing the illumination time or intensity.In order to explore the relationship between light signal and ZISO gene deeply,we detect the expression level of PSY and ZISO in phytochrome mutant(phyAphyB)and Phytochrome interaction factors’ mutant(pifQ)under different light conditions and found that dark treatment can improve PSY expression and inhibit ZISO expression in pifQ.But illumination treament can reduce expression level of PSY and ZISO in phyAphyB and pifQ.Our results showed ZISO plays important biological roles in light and dark and its mRNA levels was influenced by light signals,lose of ZISO can affects plant growth and photosynthesis.However,the expression regulation of ZISO and the mechanism of how ZISO affects plant growth still needs further research. |
