Researches On UGT-LIKE，UF1and UF2of Arabidopsis Involved In Abiotic Stresses Tolerance

Plants meet with many abiotic stress conditions during their growth and development,which is one of the major factors leading to crop yield reduction. Investigation on functionalgenes involved in abiotic stress tolerance of plant can not only reveal the molecularmechanism for abiotic stress tolerance but also provide new clues for improving croptolerance to abiotic stresses.In this study, the gene expressions, subcellular location of encoding proteins, and thephenotypes of the mutants and overexpression transgenic plants under abiotic stress ofArabidopsis UGT-LIKE, AtUF1and AtUF2were investigated. Additionally, these genefunctions in regulating actin filament dynamics were analyzed. The results are as follows:(1) The expression of UGT-LIKE was induced by actin dynamics and abiotic stress. Thetranscript level of UGT-LIKE was upregulated under Lat B and JAS treatments. NaCl andmannitol treatments also improved the gene expression. Phenotypic analysis indicates that theroot of Arabidopsis overexpressing UGT-LIKE was shorter than tha of the wild-type20d afterLat B treatment. Additionally, the actin filaments in leaves of Arabidopsis overexpressingUGT-LIKE were broken and disassembled. These results indicate that UGT-LIKE plays itsfunction in abiotic stress response and regulation of actin dynamics in Arabidopsis.(2) The expression of Arabidopsis unknown functional gene1(AtUF1) is regulated bysalt stress, dehydration stress, ABA treatment and Lat B treatment. qRT-PCR analysis showsthat the AtUF1transcript level was up-regulated under the treatments of salt, mannitol, ABA,and Lat B. Furthermore, AtUF1expression was strongly induced by cycloheximide,indicating that the AtUF1expression is modulated by an unknown negative factor.The germination of transgenic seeds overexpression of AtUF1is earlier than those of thewild type and atuf1mutant in MS medium containing150mM NaCl. Furthermore, the rootsof the transgenic plants are longer than those of the wild type on MS medium containing1.6 μM ABAfor13d, and the root length of atuf1is less than those of the wild type. These resultssuggest that AtUF1involved in plant response to salt stress is ABA-dependent. Furthermore,the root length of seedlings grown on medium containing0.3μM Lat B was investigated. Wefound that the root of the transgenic plants overexpressing AtUF1is shorter than that of thewild type, and the root of atuf1mutant is longer than that of the wild type. Additionally, wefound that the actin filaments were disassembled in leaf epidermal cells of transgenicArabidopsis overexpressing AtUF1. These results indicate that AtUF1regulates tissue growthby involved in actin dynamic dynamics.(3) The expression of unknown functional gene AtUF2was also induced by NaCl andmanitol treatments. GFP fusion protein analysis showed that AtUF2was localized inperoxisome. The growth of the seedlings overexpressing AtUF2is better that those of the wildtype and the atuf2mutant on MS medium containing0.5μM MV. These data reveal thatAtUF2is possibly involved in oxidative stress response in Arabidopsis.