Transcriptomic Analysis Of Resistance Response Of Mulberry To Meloidogyne Enterolobii

Mulberry is the important material basis for sericulture industry,mulberry diseases resulted in a serious impact on the development of sericulture.The Meloidogyne enterolobii disease of mulberry was discovered and reported in recent years,it’s led to economic losses to sericulture industry.Therefore,it is of great significance for mulberry breeding to screen out mulberry cultivars highly resistant to M.enterolobii,and explore the mechanism of mulberry resistant to M.enterolobii.In this study,we evaluated the resistant degree of twelve cultivars of mulberry cultivated in Guangdong Province by artificial inoculation.Then we compared the infection process of M.enterolobii in the resistant and susceptible mulberry cultivars,and the transcriptome technique was used to preliminarily analyse the defensive control mechanism of mulberry to M.enterolobii.It will provides theoretical basis for breeding disease-resistant cultivars.The main results are as follow:1.Resistance identification of mulberry cultivars to M.enterolobii.In this study,the changes of disease index(DI),gall index(GI),egg granule index(EI)and reproduction factor(RF)of 12 mulberry cultivars infected with M.enterolobii were determined.The results should that DI was 20.00~77.30,GI was 7.15~23.70,EI was 25.71~736.95,RF was 0.11 ~ 0.64 after inoculation for 30 days,the changes of resistance indexes was significanty different among the mulberry cultivars.EI of four resistant indexes had the highest coefficient variances.The result of clustering analysis with EI was quite same to that with four resistant indexes,this mulberry cultivars were divided into three groups(resistant,susceptible and high susceptible).Among them,Yuesang11,YuesangC44,YuesangC8,Yuesang51,Yuesang55,Yuesang119,YuesangC33 were resistant cultivars.Yuesang87,Yuesang110,YuesangC10,283 × anti 10 were susceptible cultivars.Yuesang120 was high susceptible cultivar.Then,according to the sum of subordinate function values,the resistance intensity of the mulberry cultivars were ranked.The sequence of resistance from strong to weak sucessively was: Yuesang 11,Yuesang C44,Yuesang C8,Yuesang 51,Yuesang C5,Yuesang 119,Yuesang C33,Yuesang 87,Yuesang C10,Yuesang 110,283×anti-10,Yuesang 120.2.Transcriptomic Analysis of Resistance Response of Mulberry to M.enterolobii.Through transcriptome sequencing and Denovo assembling of root samples of the resistant and susceptible mulberry cultivars at differene stages after infected by M.enterolobii,weassembled a total number of 55,894 Unigenes.There were 33,987 Unigenes annotated in Nr,Swissprot,KEGG and KOG databases.According to GO and Panthway enrichment analysis of differentially expressed genes(DEGs)and genes in key trend,we found that this genes were mainly concentrated in hormone metabolic process,plant hormone signal transduction,flavonoid biosynthesis,phenylpropanoid biosynthesis,peroxisomal and photosynthetic pathway.Then,through co-expression network analysis of key trends,we found some genes was positively correlated with resistance to M.enterolobii,such as Unigene0015083,Unigene0073272,Unigene0004006 and Unigene0000628.Unigene0015083 encodes a tabersonine 16-O-methyltransferase ROMT gene,which is involved in alkaloid biosynthesis;Unigene0073272 encodes a transcription factor,which is involved in nutric oxide accumulation in plant immunity;Unigene0004006 and Unigene0000628 encodes ERF and MYB transcription factor respectively,which are involved in plant hormone signaling.In order to verify the accuracy of transcriptome sequencing results,21 genes were selected from DEGs for RT-qPCR verification.The results showed that the sequencing results were reliable.