Molecular and Phylogenetic Identification of Fungal Taxa Associated with Soybean Anomaly in Brazil

Abstract

Soybean anomaly, characterized by immature pod and grain rot, has been reported in Brazilian soybean production fields, but the fungal taxa associated with symptomatic tissues remain poorly characterized. This study aimed to identify fungi associated with soybean plants showing anomaly symptoms using molecular and phylogenetic approaches. Symptomatic samples were collected from production fields in Mato Grosso and Rondônia, Brazil. Fungal isolates were obtained from pods, seeds, stems, and leaves, and DNA was extracted for amplification of the ITS and LSU rDNA regions. Sequences were compared with GenBank reference data using BLAST, and phylogenetic analyses were performed using Maximum Likelihood. The analyses revealed isolates belonging to Colletotrichum, Corynespora, Diaporthe, Fusarium, Moniliophthora, Neurospora, Roseograndinia, and Xylaria. Among these, Colletotrichum, Diaporthe, and Fusarium are well-documented soybean pathogens, whereas Corynespora, Moniliophthora, Neurospora, Roseograndinia, and Xylaria remain poorly documented in this host and may represent secondary or opportunistic colonizers. The findings expand molecular information on fungi associated with soybean anomaly in Brazil. However, because pathogenicity tests were not performed, the results should be interpreted as evidence of fungal association with symptomatic tissues rather than confirmation of causality.