The use of synthetic fungicide needs to be gradually reduced because of its adverse effect on human health and the environment. An integrated approach combining fungicides with biological control agents (BCAs) can be used to reduce the fungicide doses, thereby minimizing the risks associated with chemical fungicides. In this study, the combined application of a BCA Trichoderma and a fungicide hymexazol was used to manage the cowpea wilt disease caused by Fusarium oxysporum. The Trichoderma SC012 strain, which is resistant to hymexazol, was screened out and identified as T. asperellum. T. asperellum SC012 showed hyperparasitism to F. oxysporum and could penetrate and encircle the hyphae of pathogen on a medium amended or not with hymexazol. When combined with hymexazol, the population density in the rhizosphere soil of cowpea showed no significant difference compared with the treatment Trichoderma used alone. When the concentration of T. asperellum SC012 or hymexazol was halved, their combined application could control cowpea wilt disease more effectively than their individual use. The findings showed that the combination of Trichoderma and hymexazol could reduce the use of chemical fungicide, which is eco-friendly and may be an important part of integrated control of Fusarium wilt in cowpea.

Studying the interrelationship between agroecosystems and the microbiome is essential in achieving sustainable agricultural development. In particular, the relationship between the rhizosphere microbiome and crops is critical to the health and stability of agroecosystems. This study evaluated the diversity and keystone species of the cucumber rhizosphere microbiome and investigated their contributing role in cucumber growth and microbial community regulation. A total of 108 soil samples were collected from the rhizosphere and bulk soil of cucumber crops in different locations and under different cultivation modes in a high-yield area. These samples were analyzed to study the interrelationships between different cultivation modes and crop rhizosphere microorganisms. The results revealed significant regional differences in microbial communities due to microhabitat (rhizosphere and bulk soil) and geographic location. Common bacteria such as Pseudomonas, Sphingomonas, Lysobacter and Rhodanobacter were the most abundant and showed strong correlations with several other bacteria through co-occurrence networking. In addition, Flavobacterium sp. and Bacillus sp. were identified as keystone species for the rhizobia community structure. Synthetic microbial communities and pot experiments confirmed that these two keystone species could enrich the soil microbime and promote cucumber growth. Flavobacterium sp. may promote cucumber growth by regulating the rhizosphere microbial community while Bacillus sp. may influence cucumber growth by stabilizing the rhizosphere microbial biomass, further enhancing nutrient cycling efficiency and improving system stability, which in turn affected the agroecosystem. Our study demonstrates that specific keystone species are important in shaping the cucumber rhizosphere microbiome and plant growth. These results provide insights into agroecosystem-microbe interrelationships and provide a potential basis for optimizing agricultural management strategies.

Curvularia lunata (Wakker) Boed, the causal agent of leaf spot in maize, is prone to mutation, making it difficult to control. RNAi technology has proven to be an important tool of genetic engineering and functional genomics aimed for crop improvement. MicroRNAs (miRNAs), which act as post-transcriptional regulators, often cause translational repression and gene silencing. In this article, four small RNA (sRNA) libraries were generated from two maize genotypes inoculated by C. lunata; among these, ltR1 and ltR2 were from the susceptible variety Huangzao 4 (HZ), ltR3 and ltR4, from the resistant variety Luyuan (LY), and 2286, 2145, 1556 and 2504 reads were annotated as miRNA in these four sRNA libraries, respectively. Through the combined analysis of high-throughput sequencing, microarray hybridization and degradome, 48 miRNAs were identified as being related to maize resistance to C. lunata. Among these, PC-732 and PC-169, two new maize miRNAs discovered, were predicted to cleave mRNAs of metacaspase 1 (AMC1) and thioredoxin family protein (Trx), respectively, possibly playing crucial roles in the resistance of maize to C. lunata. To further confirm the role of PC-732 in the interaction of maize and C. lunata, the miRNA was silenced through STTM (short tandem target mimic) technology, and we found that knocking down PC-732 decreased the susceptibility of maize to C. lunata. Precisely speaking, the target gene of PC-732 might inhibit the expression of disease resistance-related genes during the interaction between maize and C. lunata. Overall, the findings of this study indicated the existence of miRNAs involved in the resistance of maize to C. lunata and will contribute to rapidly clarify the resistant mechanism of maize to C. lunata.

In tropical rubber-growing regions, Corynespora leaf fall disease stands as a predominant and economically significant threat to rubber trees. The toxin protein encoded by the cas5 gene is the main pathogenic factor of Corynespora cassiicola. To identify transcription factors capable of binding with the cas5 gene promoter sequence of C. cassiicola, the promoter of the cas5 gene was predicted by bioinformatics, and the 1000 bp promoter of the cas5 gene was isolated to construct a yeast one-hybrid bait vector for self-activation detection. A yeast one-hybrid cDNA expression library of C. cassiicola was constructed to screen for potential transcriptional regulators interacting with the 1000 bp promoter of the cas5 gene. The transcriptional regulators interacting with the cas5 gene were determined by the yeast one-hybrid (Y1H) point-to-point verification experiment. Y1H results showed that the bait vector did not have self-activation. The cDNA library had a titer of 2.516 × 10⁸ cfu/mL and a total clone count of 5.032 × 10⁸. Screening identified 30 candidate transcriptional regulators. Through point-to-point yeast one-hybrid verification, only one of the 30 candidate transcription factors (named CcbZIP3629) showed interaction with cas5. Molecular docking was performed using the AlphaFold3-predicted structure of CcbZIP3629, which revealed its binding to two ACGT core motifs within the promoter. These findings provide the groundwork for elucidating the regulatory mechanism of the cas5 gene, particularly by which CcbZIP3629 mediates the expression of the Cc-Cas5 toxin.