Functional Characterization Of MaMATE1, A Member Of The MATE Family From Musa Acuminata

MATE (multidrug and toxic compound extrusion family)transporters, at present, are categorized in five families according to their primary structure and mode of energy-coupling. MATE genes can transport catio dyes、aminoglycosides、many kinds of antibiotics and drugs.We have isolated a MATE gene from cDNA library of banana(Musa acuminata L. AAA group cv. Brazilian), designated MaMATE1. Analysis of sequence of MaMATE1 indicated that a MATE domain and 12 transmembrane regions existed in the gene. Analysis of alignment and phylogenetic revealed that MaMATE1 shared more similarity with MATEs in grape,Aribidopsis,and tobacco.When analysing the MaMATE1 accumulation in different organs of banana,We found that the level of MaMATE1 expression was higher in banana root,flower and fruits,suggesting it may play important role in these tissues.During the process of fruit postharvest ripening,expression of this gene enhanced in first four day and peak at the 4 d,then decreased sharply to a much low level.Exogenous ethylene can largely enhanced the expression of MaMATE1,but ethylene inhibitor only slightly inhibited expression of MaMATE1 in the whole stage of fruit ripening.To verify the sublocalization of MaMATE1,we inserted the coding region of MaMATE1 to the pCAMBIA-1304 plant expression construction driven by 35S promoter,and transformed it into onion epidermis cells by particles bombardent,the result showed that MaMATE1 protein mainly localize on the cell membrane.To characterize response of MaMATE to abiotic stress in banana,we have optimized the condition of hydroponics in advance.Under drought treatment,expression of MaMATE1 decreased both in root and leaves.When suffered from mechanical damage, accumulation of MaMATE reduced in banana leaf.Under NaCl treatment,MaMATE1 was induced both in root and leaves.Similarly,mRNA level of this gene increased in leaves when treated by UV-B,cold and ethrel,but sharply rised in root under stress of Al3+、Mn2+ and high concentration of phoxim,as well as deficiency of potassium and phosphorous.On the other hand,MaMATE exhibited little response to waterlogging stress and high concentration propiconazole.To investigate the function of MaMATE in vitro,the MaMATE1 was imported into INVSc1 yeast cells.These transgenic yeast cells enhanced their resistence to stress of NaCl、UV-B radiation、salt、cold and heavy metal,but had no change in response to drought and high temperature.According to the evidences mentioned above,we conclude that MaMATE can mediate the plant resistence to stress of NaCl、UV-B radiation、cold and heavy metal,and involve in the responsive pathway to stress of drought、mechanical damage as well as deficiency of potassium and phosphorous...