The Influence Of Low Temperature Treatment On Sugar Content In Leaves And Expression Characteristics Of Glycosyltransferase Gene Family EgrGATL In Giant Eucalyptus

Abiotic stresses like low temperature could do harm to the growth and development of plants.However,plant has elvoved different measures to respond to the unfavorable environmental conditions.Under stressful environment,the cell wall compnents and structure can be affected by glycosyltransferases which have the ability to transfer sugars to other receptor resulting in forming pectin and other important metabolism material.This can lead to stress response in plant.GATL is one of important glycosyltransferase gene families which belong to GT8(glycosyltransferase 8)super gene family.1?In Eucalyptus grandis,the soluable sugar and other monosaccharide which include arabinose and galactose increased under 4° C treatment.2?Nine GATL genes were found in Eucalyptus grandis through homolog blast method.They all have GT8 domain in amino acid sequence.Except for EgrGATL8 which has a very short sequence,the other 8 protein sequence all have DSD,HWSGKGKPW,GSLLPPFLIVF,CYFNTGVMVMD**RWR,WNQHGLGGD and R*YLAD*L* motifs which characterize them as GATL proteins.3?All nine GATLs were highly expressed in stems and roots in Eucalyptus grandis while showing low expression in leaves.Under different low temperature treatments(-8,-4,0,4,8° C),most of Egr GATL were induced to some extent,but EgrGATL7 and 9 were inhibited.The expression of EgrGATL under the 4° C condition can be divided into 3 patterns: EgrGATL1,3,8 were always induced;EgrGATL2,4,6 were induced firstly,then decreased;EgrGATL5,7,9 were inhibited.High salt(200 mmol·L-1)could also promote expression of some EgrGATLs,which includes EgrGATL3,4,5,6,7 after a period time.Inhibition for these genes were observed while the expression level of EgrGATL1,8 decreased under salt treatment.4?After 24 hours,the ABA treatment with 100 ?mol·L-1 for Eucalyptus grandis seedlings led to repress the expression of EgrGATL,whose pattern was similar to the NaCl treatment.MeJA(100 ?mol·L-1)can stimulate the EgrGATLs expression promotely.Under the drought condition,the EgrGATLs expressed the rhythms of induction,inhibition and induction again.In addition,all EgrGATLs were induced under light and inhibited under darkness.5?Subcellular localization of 4 EgrGATLs were also analyzed,the results showed that both EgrGATL1 and EgrGATL3 expressed in the membrane and nucleus;EgrGATL5 only expressed in the cell membrane whereas EgrGATL8 were seen in any part of the cell.6?EgrGALT1 were selected to overexpress in Arabidosis in order to evaluate it's function under different abiotic stress conditions;however,there is no obvious phenotypic differenence between the transformed lines and the wild type.It is likely that the GATL need interact with other genes to play a role in responding to abiotic stress.