Diversity of the Seedborne Fungi and Pathogenicity of Fusarium Species Associated with Intercropped Soybean

Abstract

<jats:p>Maize/soybean relay strip intercropping has been widely practiced in Southwest China due to its high productivity and effective application of agricultural resources; however, several seedborne diseases such as seedling blight, pod and seed decay are frequently observed causing severe yield loss and low seed quality. So far, the population and pathogenicity of the seedborne fungi associated with intercropped soybean remain unexplored. In this study, seeds of 12 soybean cultivars screened for intercropping were collected from three growing regions in Sichuan Province of Southwest China, and the seedborne fungi were isolated from the surface-sterilized seeds. Based on sequence analysis of ribosomal DNA internal transcribed spacer (rDNA ITS), 148 isolates were identified into 13 fungal genera, among which Fusarium covered 55.0% as the biggest population followed by Colletotrichum. Furthermore, Fusarium isolates were classified into five distinct species comprising F. fujikuroi, F. proliferatum, F. verticillioides, F. asiaticum and F. incarnatum through sequence analysis of translation elongation factor 1 alpha (EF-1α) and DNA-directed RNA ploymerase II second largest subunit (RPB2). Among them, F. fujikuroi accounted for 51.22% (42/82) and was isolated from 91.7% (11/12) soybean varieties. Pathogenicity assay showed that five Fusarium species were able to infect the seeds of soybean cultivar “Nandou12” and caused water-soaked or rot symptoms, while F. fujikuroi and F. asiaticum had much higher aggressiveness than other species with significant reductions of seed fresh weight and germination percentage. Accordingly, this study indicates that Fusarium species are the dominant seedborne fungi in the intercropped soybean in Sichuan, China, and this provides some useful references for the effective management of seedborne fungal diseases as well as soybean resistance breeding in maize/soybean relay strip intercropping.</jats:p>

Symptoms and pathogens diversity of Corn Fusarium sheath rot in Sichuan Province, China

“…In addition, F. meridionale was also recently reported as pathogen in root rot on soybean under monoculture and ear rot on maize 42,43 . Moreover, F. asiaticum has been reported as a major and dominant causal agent of FHB on wheat and barley in China [44][45][46] and was also detected as a pathogen causing Gibberella ear rot of maize and seedborne diseases of soybean 47,48 . Although F. meridonale and F. asiaticum were not predominant species in the present study, with low isolation frequencies, they were reported in China for the first time.…”

Influence of Peanut, Sorghum, and Soil Salinity on Microbial Community Composition in Interspecific Interaction Zone

“… Zeng et al (2019) indicated that the rhizosphere interactions in a mixture model are helpful in recruiting beneficial microbes, which are closely related to the improvement of plant quality in contaminated soil. Additionally, other typical systems of crop production, such as maize-peanut intercropping ( Li et al, 2018 ), maize-soybean intercropping ( Chang et al, 2020 ), and millet-sorghum intercropping ( Iijima et al, 2016 ), have provided evidence of change of microbial communities and enhancement of biotic or abiotic stress tolerance. Thus, the recruitment of specific microbial communities under particular production conditions is an interesting topic.…”

Evaluation of Seven Essential Oils as Seed Treatments against Seedborne Fungal Pathogens of Cucurbita maxima

“…This association between seeds and pathogens is an important means for the pathogens to spread on a large scale and a way to guarantee their survival in nature [ 7 , 8 , 9 ]. Seedborne pathogens can limit the production of many crops and can result in severe economic losses to growers [ 10 , 11 , 12 , 13 ].…”