The Effects Of Puccinia Striiformis F. Sp. Tritici Infection On Microbes In The Wheat Endosphere And Rhizosphere By 16S RRNA High Throughput Sequencing And Identification Of Novel Actinomycetes

For exploring the specific microbes in endosphere and rhizosphere of wheat and those recruited by disease and insect pest infestation, we used the wheat cultivar Mingxian 169(resistance strip rust genes have not been found now) and Puccinia striiformis f. sp. tritici CY32 as our study objects. Based on above research model, the 16 S r RNA metagenomes of microbiota in the endosphere and rhizosphere of wheat(normal and Puccinia striiformis f. sp. tritici Infected) will be sequenced to define the composition and abundance of different genera, ther efore, leading to their identification of these specific and recruited microbes. In addition, four novel actinomycetes were identificated. The results are shown below:High throughput sequencing results showed microbes in the rhizosphere of wheat were more abundant in the control group at second, seventh and twelfth day of the two groups(control: normal; experimental group: Puccinia striiformis f. sp. tritici infected); Diversity and richness are also greater than those in the experimental group except the seventh day. Analysis of 4 phylums, 23 families and 19 genera with significant difference at second, seventh and twelfth day showed that Verrucomicrobia, Alteromonadaceae, Sphingobacteriaceae, Verrucomicrobiaceae, Cryomorphaceae, Cellvibrio, Fluviicola, Luteolibacter, Niabella, Pedobacter and Sphingobacterium were unchanged in prophase, but increasing rapidly at twelfth day; This result indicated these microbes enriched by wheat. Microbes in the endosphere of wheat roots were more abundant in the control group at second and seventh day; Diversity and richness are also greater than those in the experimental group except the seventh day. Analysis of 2 phylums, 4 families and 3 genera with significant difference at second, seventh and twelfth day showed that Actinobacteria, Streptomycetaceae, Micromonosporaceae, Promicromonosporaceae, Nocardioidaceae and Actinosynnemataceae were increasing more rapidly than those in the control group. This result also indicated that these microbes also be enriched by wheat.The result of screening and isolation actinomycetes in the endosphere and rhizosphere of wheat roots(normal and Puccinia striiformis f. sp. tritici Infected) by culturable method showed thirty and twenty three strains were isolated from the rhizosphere an d endosphere of wheat root in the control group, respectively; Twenty and one hundred and nineteen strains were isolated from the rhizosphere and endosphere of wheat root in the experimental group, respectively; These indicated that actinomycetes were enriched in the endosphere of wheat roots. Preliminary identification and classification of these strains by morphological and cultural characteristics showed that there were three and nine different species of actinomycetes within the rhizosphere and endosphere of wheat roots respectively in the control group and five and thirty eight different species of actinomycetes in the experimental group, respectively. These results indicated that actinomycetes within the endosphere of the wheat roots with Puccinia striiformis f. sp. tritici infection was more abundant than that in the control group, but the richness of ctinomycetes within the rhizosphere of the wheat roots had little difference in the two groups. These strains were used to determine antifungal activities and found that actinomyecetes within the rhizosphere had no antifungal activity in the two groups; but there were 10(26.3%) strains in the experimental group had antifungal activity against at least two kinds of plant pathogenic fungi and 1(11.1%) strai n in the control group had antifungal activity against four kinds of plant pathogenic fungi. These results indicated that actinomycetes within the rhizosphere of wheat roots had no difference in antifungal activity in the control group and experimental group, but actinomycetes within the endosphere of wheat roots were much more than that in the control group, so when wheat infected by Puccinia striiformis f. sp. tritici, the wheat could recruit beneficial microbes to enhance disease resistance ability.It is found that 4 strains maybe represented novel species after analysis of the 16 S r RNA gene sequence and characterized using the polyphasic approach. It is showed that strain NEAU-Jh2-17 represented a novel species of the genus Streptomonospora and for which the name Streptomonospora halotolerans is proposed; strain NEAU-Jh3-20 represents a novel species of the genus Streptomyces, for which the name Streptomyces tyrosinilyticus is proposed; strains NEAU-Jh1-3 and NEAU-Jh2-5 represent two novel species of the genus Actinomadura, for which the names Actinomadura jiaoheensis sp. nov. and Actinomadura sporangiiformans sp. nov. are proposed.