The Class Ⅲ Peroxidase Gene IPH1 Regulates Plant Height in Rice
Peroxidase(PRX)is a marker enzyme of peroxisome,which can protect cells from oxidative damage and relieve the toxic effect of H2O2.It can also enhance the activity of natural killer cells and regu-late cell proliferation,differentiation and apoptosis.The class Ⅲ peroxidase(CⅢ PRXs)is a unique per-oxidase family in plants,which plays an important role in plant immunity by scavenging reactive oxygen species(ROS).However,the function of CⅢ PRXs in the establishment of plant architecture remains un-clear in rice.In this study,two different forms of knockout homozygous mutants iph1-1 and iph1-2 of CⅢ PRXs gene(LOC_Os12g09460)were obtained by CRISPR/Cas9.The plant height of the iph1 mu-tant was significantly higher than that of the wild type.Except for the length of the last internode,the lengths of other internodes were significantly or extremely significantly longer than that of the wild type.The investigation of agronomic traits showed that there were no significant differences in main traits such as panicle length and seed setting rate.The expression pattern analyzed by RT-qPCR showed that IPH1 was expressed in roots,stems,leaves,sheaths and panicles,and was relatively highly expressed in stems and sheaths.Subcellular localization analysis showed that IPH1 was mainly located in peroxisomes.Through further physiological analysis,it was found that the peroxidase activity in iph1 mutant was sig-nificantly reduced,while the H2O2 content was increased.These results preliminarily confirmed that IPH1 regulates the formation of plant height through the hydrogen peroxide pathway in rice,which can provide favorable gene resources for enriching the plant height regulation network and further lay a good foundation for plant architecture related biological breeding.