Multi-host species of Cercospora are associated with Cercospora leaf blight and purple seed stain of soybean
Many Cercospora spp. are multi-host pathogens. The versatility of Cercospora newly associated with Cercospora leaf blight (CLB) and purple seed stain (PSS) in soybean seems to have been historically underestimated. Herein, we assembled multilocus sequence data (seven nuclear gene regions) with sequences from 36 fungal isolates sampled from non-soybean host species from Brazil (15 species) and United States (six species), in addition to 13 isolates from soybean. Phylogenetic tools explored relationships among isolates of Cercospora obtained from either soybeans or non-soybean hosts. Cercosporin production was determined to confirm whether the isolates belong to cercosporin-producing species of Cercospora. Among the five genealogical lineages, Lineage 1 showed C. kikuchii as the only member; this species is known to infect only soybean. The remaining four lineages were multi-host Cercospora which infected soybean along with ornamental and weed species. Genealogical placements were unrelated to host association and isolates clustered according to geography. Multi-host species of cercosporin-producing Cercospora are associated with CLB and PSS of soybean.
KeywordsCercospora kikuchii DNA sequencing Fungal genetics Genetic diversity Glycine max Phylogeny Phylogeography
We are grateful to those who provided assistance collecting samples. LLB received a scholarship from National Council of Scientific and Technological Development (CNPq; 140428/2014-3) and CAPES Foundation (8781/14-1). LOO received fellowships from CNPq (PQ 305827/2015-4, PDE 200786/2015-6) and grants from the Minas Gerais State Foundation of Research Aid (FAPEMIG; PPM 00561-15), CNPq (478752/2013–0), and CAPES (PPCP–Mercosul 015/2011). TFF received a fellowship from CAPES (PNPD 2010). MGL received a fellowship from CNPq (IC 104284/2016-1). IDC received a fellowship from CNPq (IC 121557/2014-6). BHB was supported by award #1253256 from the U.S. National Science Foundation. The National Institute of Food and Agriculture, U.S. Department of Agriculture (award #1008895 to BHB) provided additional support.
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