Functional Studies Of Auxin Response Factor Gene SlARF10 In Tomato Fruit Development

The formation and development of fruit requires a series of rigorous mechanisms to regulate complex and orderly changes in molecular,biochemistry and structure.Auxin,as a plant hormone plays an important role in regulating these changes.However,the specific mechanism relating with fruit formation and development remains poorly understood.Studies have shown that two gene families known as auxin response factor(ARF)and auxin / indole-3-acetic acid(Aux / IAA)regulate the mechanism of auxin function in the process of tomato fruit formation and development.Some ARFs genes have been indicated to be involved in fruit formation and development processes and possess an important function.Auxin response factor SlARF10 is one of the members of the tomato ARFs family.This paper mainly discusses SlARF10 function in tomato fruit development.Comparing the amino acid sequence of SlARF10 showed that it contained typical ARFs conserved domain: B3-DNA domain,ARF domain and AUX/IAA domain,preliminary indicating that SlARF10 belongs to ARFs family.We studied the subcellular localization and transcriptional activation of SlARF10,finding that SlARF10 was a transcription factor localized in the nucleus but not relating with transcriptional activation.We analyzed the tissue expression pattern of SlARF10.Through online analysis of tomato gene expression database and RT-PCR detected that SlARF10 was expressed in all organs or tissues of tomato,but the expression level of fruit was significantly higher than that of other organs in fruit development period,indicating that the SlARF10 was mainly involved in the development of tomato fruit.In order to elucidate the function of SlARF10 in fruit development,we constructed overexpression and interference vectors transforming to tomatoes and then obtaining the T3 transgenic plants,finding that immature and ripe green fruit showed a dark green fruit phenotype of overexpressing plants,while RNAi inhibition showed the opposite phenotype.Measuring the chlorophyll content of green fruit period indicated that overexpressing plants contained higher than that of wild type plants,and RNAi inhibition plants also showed the opposite,lower than wild type.Our results indicated that SlARF10 plays an important role in the development and accumulation of chlorophyll in tomato fruit development.We further analyzed the changes of carbohydrate content and the expression of related gene in fruit finding that overexpressing plants contained higher than that of wild type plants,and RNAi inhibition plants lower than wild type.Meanwhile,the expression of important rate-limiting enzyme genes related to starch synthesis also undergone important changes,indicating that SlARF10 promotes the accumulation of carbohydrate substances in fruit by affecting the expression of starch synthesis genes in tomato fruit development.In summary,our study presented that SlARF10 as the member of the ARF family in tomato,plays an important role in the formation and development of tomato fruit,function in controlling the expression of starch related enzymes,thereby promoting the accumulation of carbohydrates.Our study further expands the understanding of the ARF family genes and identifies their function in the development of tomato processes.