Transcriptional Regulation Of Loquat Fruit Lignification By MADS

Loquat(Eriobotrya japonica)is rosaceae perennial woody fruit tree.According to the color of flesh,it could be classified into two major types,as red flesh type and the white flesh type.During postharvest storage,the red flesh type loquat fruit showed typical lignification phenomenon,with accumulation of lignin and increasing of firmness.Low temperature(<5?)storage could trigger chilling injury induced lignification.A few of transcription factors were reported as regulators on loquat fruit lignification,including EjMYB8.In order to characterize the up-stream transcription factors for fruit lignification regulation,EjMYB8 was chosen in present research for further exploration.The main results are as follows:1.Yeast one-hybrid libraray screening for EjMYB8 promoter.892 bp promoter sequence of EjMYB8 was isolated,using genome-walking technology.113 putative transcription factors were found through Yeast one-hybrid library screening using EjMYB8 promoter.However,individual yeast one-hybrid assay analysis indicated that only EjMADS could physically interact with EjMYB8 promoter,while the other transcription factors could not.2.EjMADS is a transcriptional repressor on lignification.Dual luciferase assayindicated that EjAMADS significantly repressed EjMYB8 promoter.Furthermore,low temperature conditioning(LTC)and heat treatment(HT)both up-regulated the expression of EjMADS.Taken together the results of dual luciferase assay and gene expression,EjMADS is a negative regulator on loquat fruit lignification.In conclusion,EjMADS is a novel regulator for loquat fruit lignification via regulation on EjMYB8,which provided a new example of transcriptional network of lignification in loquat fruit.