This study investigates the potential role of Acrocalymma dark septate endophytic (DSE) fungi in promoting the growth of Solanum lycopersicum (tomato). Recognized as important symbionts that enhance plant growth and resilience under stress, particularly Acrocalymma species, DSE fungi were the focus of this investigation. Specifically, four stains isolated from gramineous plant roots (Acrocalymma sp. E00677, Acrocalymma vagum E00690, Acrocalymma chuxiongense E01299A, and Acrocalymma chuxiongense E01299B) were examined. Morphological characteristics were observed using three different media, confirming typical DSE traits such as dark pigmentation and septate hyphae. Phylogenetic analysis using six genetic markers (ITS, LSU, SSU, tef1, rpb2, and tub2) placed the strains within the Acrocalymma genus. Co-culture test and physiological index measurements showed that all strains significantly enhanced root development, as evidenced by an increased root-to-shoot ratio and a higher number of lateral roots. Additionally, the Acrocalymma DSE strains elevated chlorophyll a, chlorophyll b, and total chlorophyll content, suggesting improved photosynthetic efficiency. Anthocyanin levels were also increased in the tomato leaves, indicating enhanced antioxidative defense mechanisms. Among these strains, Acrocalymma vagum E00690 exhibited the most substantial effect on root activity. The widespread presence of 325 Acrocalymma isolates from 25 countries underscores its broad ecological adaptability. These findings suggest that Acrocalymma DSE fungi positively influence tomato growth, with potential implications for improving plant resilience under environmental stress. This study highlights the importance of further exploring DSEs, particularly Acrocalymma fungi, to better understand their ecological roles in agricultural practices, particularly in tomato cultivation.

The genus Microcera belonging to the family Nectriaceae, includes fungi that cause diseases in both fruit trees and scale insects. During our investigation of pathogens and insects on economically important plants in Zhejiang Province, China, a nectriaceous fungus with flame-like conidiomata was found associated with the bark of Rosaceae plants and the scale insect Pseudaulacaspis pentagona, which colonizes the bark. Using maximum likelihood and Bayesian inference phylogenetic analyses based on multi-locus sequence data from ITS, LSU, acl1, act, cmdA, his3, rpb1, rpb2, tef1, and tub2, we determined that this fungus clusters with M. pseudaulacaspidis, M. kuwanaspidis, and M. coccophila within the Microcera clade. Pairwise homoplasy index tests showed no significant evidence of recombination between this species and the related taxa, confirming it as a novel species. This new species, Microcera gongcheniae, is characterized by masses of orange to red, flame-like sporodochia formed on both the bark and the scale insect, as well as hyaline, cylindrical, slightly curved macroconidia formed in the sporadochia. The macroconidia of M. gongcheniae are longer than those of its sister species M. pseudaulacaspidis.