A MATE Transporter Gene Of Zea Mays Regulates Leaf Senescence,Hypocotyl Elongation And Seed Size

The mutidrug and toxic compund extrusion(MATE)family is a secondary cation transpoters which has participated in multiple physiological functions during plant development.Although a growing list of MATE transporters are being characterized,the functions of the majority of MATE family members remain poorly understood.The function of ZmMATE884(GRMZM2G423884)has been studied by reverse genetics in this research.(1)In this study,maize MATE protein family gene ZmMATE884(GRMZM2G423884)was cloned from maize whole genomic DNA.Phylogenetic tree of ZmMATE884 with 56 Arabidopsis MATE transporter family showed that ZmMATE884 belong to the ABS3 subfamily.Homologous sequence alignment showed highly protein sequence similarities between ZmMATE884 and PfMATE,indicated that ZmMATE884 protein has 12 transmembrane domains as well.(2)The results of quantitative RT-PCR showed that the transcription level of ZmMATE884 gene was relatively high in the roots and foliage,indicated a tissue-specific expression pattern of ZmMATE884.The results of subcellular localization analysis showed that the ZmMATE884 protein was partially co-located with the specific marker protein of the original vacuole / secondary endosome,trans-Golgi / early endosomes and Golgi / endosomes,indicated that ZmMATE884 protein is distributed in the different vesicle structures of endosome formation and transportion process.(3)Over expression mutants of ZmMATE884 was constructed by Agrobacterium tumefaciens infection technique.The hypocotyls of overexpression mutants were significantly shorter than wild type germination for 6 days or 12 days in the dark.The same result has been observed in the plant growth under persistent light for 7 days.Exogenous addition of sucrose could promote the elongation of transgenic plants and wild-type hypocotyls,but the hypocotyl length of transgenic plants was still shorter than that of wild type.These results showed that ZmMATE884 gene was involved in the negative regulation of plant hypocotyl elongation,and the regulation of ZmMATE884 gene for hypocotyls was different from sucrose.(4)Over expression mutants of ZmMATE884 has smaller and lighter seeds than that of wild type.Indicating that ZmMATE884 gene involved in the regulation of plant seed size.(5)Over expression mutants of ZmMATE884 showed phenotype of earlier flowering and accelerated leaf senescence.It also showed early leaf senescence phenoyptes under C-starvation.This result Indicate that overexpression of ZmMATE884 gene can accelerate the senescence of plant leaves.(6)The overexpression of ZmMATE884 can restore phenotype of ABS3,ABS4,ABS3L1 and ABS3L2 co-deletion mutant mateq to wild type,indicated that ZmMATE884 has similar function to ABS3,ABS4,ABS3L1 and ABS3L2 genes.