Image Credit: Kathryn Bushley
Within the framework of JGI "Community Sequencing Project: Defensive Mutualism of Fungal Root Endophytes of Soybean" CSP project, we are investigating the potential role of fungal endophytes isolated from soybean roots in protecting the plant from two devastating root plant pathogens: 1) the root rot fungus causing Soybean Sudden Death Syndrome (Fusarium virguliforme) and 2) the soybean cyst nematode (Heterodera glycines). These fungi were screened for either anti-fungal or anti-nematode activity in-vitro and genome, transcriptome, and metabolome sequencing will address possible mechanisms of antagonism against these pathogens.
This Nectriaceae sp. isolate was obtained from surface sterilized soybean roots, but closely related isolates have also been found to parasitize eggs within the cysts of the soybean cyst nematode (Haarith et al., 2020) and likely the same species as another Nectriaceae sp. isolate from our community sequencing project (312A_T17_2). These two isolates group most closely taxonomically with fungi in the genus Dactylonectria, which was recently circumscribed based on multi-gene DNA data and morphological comparisons that reevaluated relationships among members of the genus Ilyonectria and closely related taxa (Lombard et al., 2014). Many members of Dactylonectria are plant pathogens, including Dactylonectria macrodidyma (previously known as Ilyonectria macrodidyma), which causes black foot root rot diseases of grape vines and horticultural woody crops. Dactylonectria spp. are also common soil fungi and have also been isolated as endophytes of grape vines (Gramaje et al., 2020) and Arabidopsis roots (Mesny et al., 2021). Various secondary metabolites have also been isolated from Dactylonectria, particularly resorcylic acid lactones that may play a role in virulence of root rot pathogens in the genus (Walsh et al., 2022).
References:
- GRAMAJE, D., BERLANAS, C., MARTÍNEZ-DIZ, M. D., DIAZ-LOSADA, E., ANTONIELLI, L., BEIER, S., GORFER, M., SCHMOLL, M. & COMPANT, S. 2020. Comparative Genomic Analysis of Dactylonectria torresensis Strains from Grapevine, Soil and Weed Highlights Potential Mechanisms in Pathogenicity and Endophytic Lifestyle. Journal of Fungi, 6, 23.
- HAARITH, D., KIM, D. G., STROM, N. B., CHEN, S. Y. & BUSHLEY, K. E. 2020. In Vitro Screening of a Culturable Soybean Cyst Nematode Cyst Mycobiome for Potential Biological Control Agents and Biopesticides. Phytopathology, 110, 1388-1397.
- LOMBARD, L., VAN DER MERWE, N. A., GROENEWALD, J. Z. & CROUS, P. W. 2014. Lineages in Nectriaceae: re-evaluating the generic status of Ilyonectria and allied genera. Phytopathologia Mediterranea, 53, 515-532.
- MESNY, F., MIYAUCHI, S., THIERGART, T., PICKEL, B., ATANASOVA, L., KARLSSON, M., HÜTTEL, B., BARRY, K. W., HARIDAS, S., CHEN, C., BAUER, D., ANDREOPOULOS, W., PANGILINAN, J., LABUTTI, K., RILEY, R., LIPZEN, A., CLUM, A., DRULA, E., HENRISSAT, B., KOHLER, A., GRIGORIEV, I. V., MARTIN, F. M. & HACQUARD, S. 2021. Genetic determinants of endophytism in the Arabidopsis root mycobiome. Nature Communications, 12, 15.
- WALSH, J. P., MCMULLIN, D. R., YEUNG, K. K. C. & SUMARAH, M. W. 2022. Resorcylic acid lactones from the ginseng pathogen Ilyonectria mors-panacis. Phytochemistry Letters, 48, 94-99.
