The Transcriptome Analysis Of Bitter Melon In Response To Powdery Mildew Infection

Powdery mildew is one of the major threats in the production of melon vegetables.Its occurrence severely restricts the yield and quality of bitter gourd causing huge economic losses.Mormordica charantia.L is one of the important melon vegetables in China,in this study,the germination conditions of conidia of bitter gourd powdery mildew were studied,and transcriptome analysis between different resistant bitter gourd strains and powdery mildew was conducted.The conidia of powdery mildew of bitter gourd preserved in the living body after purification was used as material to obtain bitter gourd powder germination rate of conidia under different light quality,light time,temperature,humidity,p H,oxygen supply,carbon and nitrogen source.Then use the powdery mildew of bitter gourd preserved in vivo to inoculate high-generation inbred hai09-1（sense）and hai09-2（resistant）bitter gourd strains.Transcriptome sequencing was performed on the bitter gourd leaves at 12,24,36,48,72,and 96 hours after inoculation and the leaves of bitter gourd without inoculation with powdery mildew at 0 hours.And transcriptome analysis of powdery mildew resistance was carried out.1.The suitable temperature range for conidia germination of powdery mildew of bitter gourd is 20-30℃,the optimal germination temperature is 25℃,the lethal temperature is 48℃10 min,the optimal relative humidity for conidia germination is100%,the optimal p H is 7,the most dark environment is the most suitable for spore germination,the germination rate of conidia under total oxygen conditions is 2.63%,21.13%,and 23.76%,respectively,which is always significantly higher than that of semi-oxygen（germination rates were 0.84%,3.83%,11.07%）and anaerobic（germination rates were 0.00%,0.10%,1.10%）treatment;purple light is not conducive to conidial germination,red,yellow and green light on the meristem spore germination has a certain promoting effect;balsam pear powdery mildew prefers glucose,mannitol has a certain promoting effect,polysaccharides are not conducive to the use of conidia;nitrogen source inhibits the germination of powdery mildew conidia.2.The main differences between hai09-1 and hai09-2 in response to powdery mildew infection are autophagy-others（csv04136）,MAPK signaling pathway（csv04016）,plant hormone signal transduction（csv04075）,plant pathogen interaction（csv04626）,phenylpropane biosynthesis（csv00940）pathway.3.Comparative analysis of the differential gene expression levels of bitter gourd in response to powdery mildew stress pathway.Among the genes encoding CNGCs protein（LOC111024714 and LOC111007411）were suppressed after 48 hpi in hai09-1,and induced expression in disease-resistant hai09-2.LOC111021283,a coding gene of Ca M,was up-regulated by 48-96hpi in hai09-2,while the expression of 48hpi was suppressed until 96hpi in hai09-1.Four related genes novel.481,LOC111015347,LOC111025422 and LOC111008521 in Rboh were up-regulated in hai09-2.One of the genes encoding disease-related protein PR1（LOC111017362）was not induced in12hpi resistant and susceptible balsam pear,and then showed an overall upward trend,the expression of which in the resistant balsam pear began to be up-regulated in 24hpi,earlier than that of susceptible balsam pear（36hpi）,and the relative expression was higher than that of susceptible balsam pear.The expression of another gene（LOC1110173740）was inhibited in susceptible balsam pear,the early stage of resistant balsam pear was inhibited,and 48hpi began to express at a high level.It is concluded that the optimum temperature for conidia germination of balsam pear powdery mildew is 25℃,lethal temperature is 48℃,10 minutes;prefer high humidity,dark and neutral environment,aerobic,glucose-like,no nitrogen source is needed for germination.Short wave is more conducive to germination of conidia of powdery mildew of bitter gourd.In response to powdery mildew infection of resistant and susceptible balsam pear strains,and the difference of disease resistance was reflected between 36-72hpi,hai09-2 could quickly mobilize more genes to resist powdery mildew infection.In the aspects of resistance signal transduction and autophagy of balsam pear powdery mildew,resistant balsam pear could respond more quickly to powdery mildew infection than susceptible balsam pear in the early stage,while susceptible balsam pear was significantly inhibited in the later stage.There are differences in calcium signal transmission ability of resistant and susceptible balsam pear under powdery mildew stress.Resistant balsam pear can transmit Ca²⁺signal more quickly and induce defense responses such as cell wall strengthening and hypersensitivity.There were differences in the ability of powdery mildew to synthesize the pathogen-related protein PR1.The expression of resistant balsam pear was induced in the middle stage of infection,while the synthesis of susceptible balsam pear was inhibited,which may lead to the difference of resistance between them.