Clone And Functional Analysis Of JAL30 In Arabidopsis

Lectin is a kind of glycoproteins or sugar-binding proteins extracted from animals and plants.The reaction between lectin and carbohydrates,glycoproteins and glycosylated glycolipid are reversible and specific,no structure change within sugar.In plants,proteins involved in signal transmission or conversion are glycoproteins whose residues at the end of the sugar chain can be specifically recognized and bound by lectins,thereby eliciting a specific interaction between the lectin and the glycoprotein and further elicited downstream of a series of biochemical signal cascade reactions.Therefore,plant lectins are with great research value which are worthy of further study.Jacalin is a group of plant specific lectin which was first identified in jackfruit.JAL30 was reported to play an important role in resistance to herbivore.Our previous studies found that JAL30 protein level and post-translational modification were regulated by Brassinosteroids(BRs).BRs are a group of important steroid hormones in plants that play an important regulatory role in the various stages of plant growth and development,as well as in the process of coping with various biological and abiotic stresses.However,whether JAL30 plays an important role in BR signaling pathway and the involved response mechanism is still unclear.JAL30 gene was first cloned from Arabidopsis and we also constructed the 35S::JAL30-GFP expression vector to obtain multiple transgenic lines.Phenotypic observations showed no significant abnormalities in transgenic plants.We also purchased the mutant plants of JAL30,nor did they show the clear phenotype.Considering that lectin proteins mainly regulate plant growth through a short-term response manner,the overexpression lines and mutants do not produce morphological changes in the phenotype.Meantime,we performed transient expression assay in tobacco.Results showed that this protein highly expressed in nucleus and cytoplasm,which may benefit for JAL30 to fulfill intracellular function.Study showed that JAL30 responded to BR and other inducer,thus we treated the transgenic lines with BR and hormone Jasmonate Methyl(JAMe),and analyzed from transcriptional and translation level.Results showed that BR treatment did not significantly increase the expression of JAL30 at the transcriptional level.At the protein level,BR treatment increased the expression of JAL30,but repressed by pretreated with PPZ,the inhibitor of endogenous BR synthesis.PPZ probably affected the expression of JAL30.Besides,JAMe promoted the expression of JAL30 protein.It's known that JAMe is related to defense system in plants,and BR is essential for plant growth.Consistently,our results showed that JAL30 are both regulated by BR and JAMe indicating that JAL30 plays an important role in plant growth system.We also performed immunoprecipitation and mass spectrometry(IP-MS)with JAL30 overexpression plants.JAL30 was immunoprecipitated from total protein extract.The interaction protein was analyzed by mass spectrometry.We found three phosphorylation sites on JAL30 and 53 putative interacting proteins.All these results showed that JAL30 participates in several signal pathways to mediate plant growth,and it is a key component connecting the plant growth and immunity resistance signal.Our results provide experimental supports for the further functional studies and regulation mechanism of JAL30 protein study.