Comparison On The Community Structures Of Endophytes From Wild Rosa Germplasms With Two Different Powdery Mildew Resistance

The wild Rosa with strong powdery mildew resistance is the most important germplasms for improving Rosa hybrid powdery mildew resistance.Previous studies have indicated that endophyte can improve host plant’s disease resistance.Therefore,fungal endophytic community of Rosa multiflora(strong resistant to powdery mildew)and Rosa multiflora var.carnea(susceptible to powdery mildew)at the different developing stage of powdery mildew were studied,and the specific or dominant endophytic fungi(EF)in Rosa multiflora were investigated.Total DNA of each sample were extracted,and the associated fungal endophytic communities were analyzed using Illumina Miseq sequencing,and the differences on fungal endophytic communities of two different resistance samples of wild Rosa were compared.The main results were showed as follows:1.The average high quality sequences of 30 samples of Rosa multr-flora and 30 samples of Rosa multiflora var.carnea were 67292 and 66725,respectively.The average length of sequences was ranged from 327 bp to 382 bp.2.The computational analyses of Alpha diversity showed that,before the outbreak of PM(powdery mildew),the number of EF in Rosa multiflora var.carnea was higher than that in Rosa multiflora(P>0.05),and the richness of EF in Rosa multiflora var.carnea was significantly higher than that in Rosa multiflora,too(P<0.05).Contrary to this,at the middle and late stage of PM,the number of EF in Rosa multiflora was higher than that in Rosa mulltiflora(P>0.05),and the richness of EF in Rosa multiflora was higher than that in Rosa multiflora,too(P>0.05).However,there was no significant difference on the diversity index of the same plant tissue(stems or leafs)of the same plant species at the different developing stage of PM.3.The EF from two wild Rosa species belonging to 5 phyla,17 classes,43 orders,86 families,157 genera and 208 species.Before the outbreak of PM,the dominant genera of different resistance samples were both Botryotinia and Alternaria.However,in the outbreak of PM,in May,the dominant genera of Rosa multiflora were Alternaria(30.33%of stems and 60.47%of leafs),Neofusicoccum(24.77%of stems),while the dominant genera of Rosa multiflora were Alternaria(63.43%of stems and 58.95%of leafs),Botryotinia(12.62%of leafs).In June,the dominant genera of Rosa multiflora were Alternaria(29.94%of leafs),Rhodosporidium(15.64%of stems),Botryotinia(11.14%of leafs),while the dominant genera in Rosa multiflora var.carnea were Botryotinia(26.97%of stems and 15.76%of leafs),Alternaria(18.09%of stems and 39.05%of leafs),Capnodiales sp.(19.07%of stems).After the outbreak of PM,in July,the dominant genera in Rosa multiflora were Botryotinia(25.25%of stems and 12.70%of leafs),Alternaria(11.94%of stems and 23.53 of leafs),Rhodosporidium(20.28%of leafs),while the dominant genera in Rosa multiflora var.carnea were Alternaria(26.33%of leafs),Botryotinia(25.51%of stems and 15.61%of leafs),Rhodosporidium(21.04%of stems and 19.20%of leafs),Podosphaera(13.25%of leafs).In August,the dominant genera of Rosa multiflora were Alternaria(20.04%of stems),Passalora(16.84%of leafs),Diaporthe(16.23%of stems),while the dominant genera of Rosa multiflora var.carnea were Capnodiales sp.(40.11%of stems),Alternaria(11.85%of stems).These results showed that Neofusicoccum,Rhodosporidium may play an important role in strong PM resistance of Rosa multiflora.With different developing stages of PM,the results of the correlation analysis on the abundance of dominant genera(P<0.05)were as follows:There were significant positive correlations on the following dominant genera(P<0.05):Botryotinia and Alternaria,Neofusicoccum and Rhodosporidium,Passalora and Rhodosporidium or Mycosphaerella.There were significant negative correlations on the following dominant generas(P<0.05):Botryotinia and Passalora or Mycosphaerella,Alternaria and Passalora or Rhodosporidium or Mycosphaerella.In addition,the generas with the higher variation in its abundance were Rhodosporidium,Phomopsis,Dioszegia,Podosphaera,Entoleuca,Rosellinia and Eutypella.They may be related to the outbreak of PM.4.Beta diversity analysis(cluster analysis,PCoA analysis and differences test between groups)showed that:EF communities of the same resistance sample were similar.At the outbreak of PM(May and June)),EF communities in stems from two different PM resistance plant species were similar-The results of PCoA were based on the first principal component(29.1%)and the second principal components(18%).Before the outbreak of PM,EF community in stems of Rosa multiflora was different from other samples.In addition,there were significant differences in different groups,species or stages of EF community in different resistance samples(P<0.05).