Allophoma species (Pleosporales: Didymellaceae) associated with Thunbergia grandiflora in Guangxi Province, China

Didymellaceae species associated with tea plant (Camelliasinensis) in China

Tea plant is one of the most important commercial crops worldwide. The Didymellaceae fungi can cause leaf blight disease of tea plant. In this study, 240 isolates were isolated from tea plant leaves of 10 provinces in China. Combined with multi-locus (ITS, LSU, RPB2 and TUB2) phylogenetic analysis and morphological characteristics, these isolates were identified as 25 species of six genera in Didymellaceae, including 19 known species Didymellacoffeae-arabicae, D.pomorum, D.segeticola, D.sinensis, Epicoccumcatenisporum, E.dendrobii, E.draconis, E.italicum, E.latusicollum, E.mackenziei, E.oryzae, E.poaceicola, E.rosae, E.sorghinum, E.tobaicum, Neoascochytamortariensis, Paraboeremialitseae, Remotididymellaanemophila and Stagonosporopsiscaricae, of which 15 species were new record species and six novel species, named D.yunnanensis, E.anhuiense, E.jingdongense, E.puerense, N.yunnanensis and N.zhejiangensis. Amongst all isolates, D.segeticola was the most dominant species. Pathogenicity tests on tea plant leaves showed that E.anhuiense had the strongest virulence, while E.puerense had the weakest virulence. Besides, D.pomorum, D.yunnanensis, E.dendrobii, E.italicum, E.jingdongense, E.mackenziei, E.oryzae, E.rosae, E.tobaicum, N.mortariensis, N.yunnanensis, N.zhejiangensis and R.anemophila were non-pathogenic to the tea plant.

Native forests transformed into cash crops reduced soil multi-functionality by modifying the microbial community composition and keystone species' abundance in the Jianghuai Hilly Region

Conversion of native forest to cash crops is the predominant form of land use change in the Jianghuai Hilly Region. However, how plantations with different cash crops affect the soil multi-functionality is not well documented. In this study, we collected three kinds of cash crops soils (vegetable, orchard, and tea) and forest soil, to systematically review the relationship between soil microbial communities and soil multi-functionality. Soil multi-functionality had decreased in vegetable and orchard as compared to native forest, whereas tea plantation had no significant effects on soil multi-functionality. The results also showed that cash crop plantations decreased soil multi-functionality by shifting keystone species' abundance, for forest, vegetable, and orchard, the keystone species that were classified as module hubs in the bacterial co-occurrence network significantly negatively contributed to soil multi-functionality, but the keystone species categorized as module hubs in fungal co-occurrence network positively affected soil multi-functionality. Multiple soil properties were the drivers of the soil microbial community; thus, indicating that the altered soil properties under cash crop plantations were vital in determining microbial composition and biological processes. These results identified that sustainable management strategy in cash crop plantation needed to be developed for improving soil multi-functionality.

Pseudomonas sivasensis 2RO45 inoculation alters the taxonomic structure and functioning of the canola rhizosphere microbial community

Inoculation with plant growth-promoting rhizobacteria (PGPR) is an eco-friendly sustainable strategy for improving crop productivity in diverse environments under different conditions. Our earlier study demonstrated that Pseudomonas sivasensis 2RO45 significantly stimulated canola (Brassica napus L. var. napus) growth. The aim of the present study was to investigate the structural and functional dynamics in the canola rhizosphere microbiome after inoculation with PGPR P. sivasensis 2RO45. The results based on alpha diversity metrics showed that P. sivasensis 2RO45 did not significantly alter the diversity of the native soil microbiota. However, the introduced strain modified the taxonomic structure of microbial communities, increasing the abundance of plant beneficial microorganisms, e.g., bacteria affiliated with families Comamonadaceae, Vicinamibacteraceae, genus Streptomyces, and fungi assigned to Nectriaceae, Didymellaceae, Exophiala, Cyphellophora vermispora, and Mortierella minutissima. The analysis of community level physiological profiling (CLPP) revealed that microbial communities in the P. sivasensis 2RO45 treated canola rhizospheres were more metabolically active than those in the non-treated canola rhizosphere. Four carbon sources (phenols, polymers, carboxylic acids, and amino acids) were better metabolized by the microbial communities from the rhizosphere of plants inoculated with the P. sivasensis 2RO45 than non-inoculated canola rhizospheres. Based on the community-level physiological profiles, the functional diversity of the rhizosphere microbiome was altered by the P. sivasensis 2RO45 inoculation. Substrate utilization Shannon diversity (H) index and evenness (E) index were significantly increased in the treated canola plants. The study provides new insight into PGPR-canola interactions for sustainable agriculture development.