Resistance Evaluation Of Chickpeas To Ascochyta Rabiei And Differential Transcriptome Expression Analysis Of Resistant Chickpea In Seedling

Chickpea(Cicer arietinum L.),an annual leguminosas herbaceous crop,which characterized with rich nutrition,extensive use and excellent tolerance to infertile&drought,and widely distributed aroud the world.Mulei,Changji of Xinjiang is the main producing areas of chickpea in China.Following the occurence and epidemics of Ascochyta Blight(pathogen is A.rabiei),chickpea cultivation was severely impaired at this region.The present study depend on the resistance evaluation of 6 chickpea resources to A.rabiei and infection process characterization of A.rabiei to chickpea resistance resource,differential expression analysis of the chickpea seedling transcriptome with the infection of A.rabiei were carried out.Results:(1).The chickpea resistance evaluation,“Xixuan 03”(Desi)showed R in indoor evaluation in2016,showed R and MR in field and indoor evaluation in 2013s;“216”showed MR in the lab in 2016,showed R and MR indoor and in field respectively in 2013s;“169”and“177”showed HS in the three times evaluation;“224”showed S in the three times evaluation;“Wushen”showed HS in lab evaluation in 2016,showed HS and S in lab and in field evaluation in 2013s.(2).The invasion process investigation of A.rabiei to chickpea:Under the dyeing treatment,12?24 h after inoculation,spores were accumulate on the epidermis of chickpea leaves;from 24 to 48 h after inoculation,a large number of spores were elongate,and accumulated around the stomata in the leaves,or around the leaf villi,the partially elongated spores form a loop on the fluff of the chickpea leaves to strengthen the attachment.At the same time,partially elongated hyphae penetrated into the stomata of chickpea leaves and began to invade the epidermis of chickpea leaves;48-96 h after inoculation,the number of elongations of A.rabiei spores increased gradually,and the spores of pathogenic were elongated through the skin of chickpea leaves which invaded through stomata cell of chickpea.(3).Different expression analysis of chickpea with the inoculation of A.rabiei:a total of 60.75 Gb clean data was obtained among the 10 chickpea samples,the Q30 of each sample was higher or equal with 91.71%.The alignment efficiency between each samples with the chickpea genome ranged from 88.16%to 93.28%.In the 10 sequencing chickpea samples,the number of SNP sites explored was among 9,415?10,628.25,282 genes were aligned to the chickpea genome and 950 new annotated genes were discovered,of which 813 were functionally annotated.With Fold Change?2 and FDR<0.01 as the screening criteria,338 DEGs were obtained from the new annotated genes,which accounted for 41.57%of functional annotated genes.Among the chickpea genes which aligned with ckickpea genome have positive result,7,410 DEGs were found and accounting for 33.51%in aligned genes.Between the compare group of 36 hpi and 96 hpi,101 overlapping DEGs were obtained in the new annotated gene,of which 85 DEGs had the same expression pattern in different treat time point.It mainly involve in biological processes such as intracellular transport,nucleic acid binding protein function,plant pathogen interaction and transcription factors regulation.Among the genes that were positive with the chickpea genomic alignment,3,573 DEGs were obtained in 36 hpi gourp,in which 2,088 DEGs were up-regulated and 1,485 DEGs were down-regulated,accounting for 58.4%and 41.56%in the total DEGs of36 hpi.7,253 DEGs were found in 96 hpi group,in which 3,332 DEGs were up-regulated and 3,921 DEGs were down-regulated,accounting for 45.94%and 54.06%in the total DEGs of 96 hpi group.Between these two groups,3,010 overlapping DEGs were found.Among the overlapping DEGs,2,990 DEGs had the same expression pattern in different treat time point,and mainly involved in post-transcriptional modifications,cell wall synthesis and phytohormonal signal transduction.Depend on the bioinformatic database KEGG,COG,Swiss-Prot,GO and nr,there are 849,1,671,2,830,3,057 and 3,557 DEGs have been annotated respectively in 36 hpi group;1,628,3,262,5,618,6,100 and 7,216 DEGs have been annotated respectively in 96 hpi group.16 DEG were randomly selected to using in the q RT-PCR verification,the expression pattern of these selected genes have same variation trend through q RT-PCR and transcriptome sequencing,results that the transcriptome sequencing data were reliable.Conclusions:(1).“Xixuan03”is a stable resistance resource for chickpea resistance breeding.(2).During 24?48 h after inoculation is the critical period time of A.rabiei invade into chicpea surface organism.(3).At 36 hpi,the chickpea transcriptome was regulated mainly in terms of photosynthesis decreasing,porphyrin and chlorophyll metabolism decreasing and plant-pathogen interaction enhancement.The regulate genes of ER-TU family recognition factor caused the inhibition of plant photosystem self-repair functions,heat shock protein-regulated genes,and phytohormone signaling pathway-regulated genes regulated genes of NOS signaling involved in the induced hypersensitivity reaction are all different expressed.At 96 hpi,chickpea transcriptome regulation mainly concentrated in photosynthesis enhancement,ribosomal metabolism reduceding and photosynthetic nitrogen metabolism strengthen.At this time,the differentially expressed genes are mainly belonging to the regulate gene which involve in signal transduction pathways of plant-pathogen recognition:NOS signal transduction regulatory genes and Ca²⁺transduction regulatory genes.Phytohormone signaling pathway regulatory genes are also take important role in this time point.