Characterization of Rhizoctonia-Like Fungi Isolated from Agronomic Crops and Turfgrasses in Mississippi

Abstract

Twenty-three isolates of Rhizoctonia spp. from agronomic crops and turfgrasses were characterized by cytological and pathological methods in order to establish the identity, pathogenicity, and virulence of Rhizoctonia spp. and anastomosis groups that occur on these hosts in Mississippi. Twelve isolates were identified as R. solani, including the five anastomosis groups (AGs) AG-1-IB, AG-2-2, AG-4, AG-5, and AG-13. Rhizoctonia zeae, R. oryzae, and eight binucleate Rhizoctonia sp., including R. cerealis, also were identified. R. solani AG-4 isolates were consistently the most virulent isolates on all hosts in pathogenicity evaluations. Pathogenicity of AG-2-2 and AG-5 isolates, binucleate Rhizoctonia spp., and R. oryzae varied between hosts. Two AG-2-2 isolates from bermudagrass or wheat were determined to be clonal isolates, with numerous self-anastomosis reactions. R. solani (AG-1-IB) was pathogenic on all graminaceous hosts. R. cerealis produced sharp eyespot symptoms on wheat and corn and minimal symptoms on cotton and soybean. This is a first report of R. cerealis as a pathogen of corn. R. zeae isolates were pathogenic on all hosts, including cotton and soybean. These results indicate that a diverse group of Rhizoctonia spp. occurs as pathogens on a wide variety of agronomic crops and turfgrasses in Mississippi.

Susceptibility of Wheat Varieties to Soil-Borne <i>Rhizoctonia</i> Infection

“…Here we included data on virulence of strains of the above five teleomorph genera, all of them attacked germinating seeds of cereals tested. Our results approve presumtion of Tomaso-Peterson and Trevathan [52] that the new for Europe pathogen, R. zeae, is considered as a hazard for wheat cultivation, with special regard to warm climate areas.…”

Characteristics and diversity of Rhizoctonia spp. population in soil of selected forest bare-root nurseries in Poland

“…Fungi belonging to the Rhizoctonia genus represent a wide range of pathogenic, non-pathogenic and mutualistic species [9]. Most studies on this group of fungi, known to attack more than 200 different species of plants, relate to agricultural plants, while only few researchers have studied this group of organisms in forest nurseries [4,6,[10][11][12][13][14][15][16][17][18][19][20][21][22].…”

Genome-Wide Identification of M35 Family Metalloproteases in Rhizoctonia cerealis and Functional Analysis of RcMEP2 as a Virulence Factor during the Fungal Infection to Wheat

“…Necrotrophic pathogens thrive on dead host tissues. They often secrete effectors and phytotoxic secondary metabolites, trigger ROS excessive accumulation in host plants, and induce plant cell death, consequently facilitating the growth of necrotrophic pathogens in host plants [10,14,36]. In rice blast fungus M. oryzae, Avr-Pita, belonging to the M35 metalloprotease family, acts as an effector and its M35 domain directly interacts with the rice resistance protein Pi-ta, which confers rice blast resistance [26].…”

“…Since the late 1990s, China has become the largest epidemic region where more than 6.67 million ha of wheat plants can be infected by R. cerealis annually [7,8]. In addition, R. cerealis can also infect sugar beet, cotton, potato, several legumes, and turfgrasses, leading to root rot disease and yellow 10]. To improve using host-inducing gene silencing strategy in the resistance of wheat and other plants to R. cerealis, it is necessary to explore and further study the effectors or virulence factors of the fungal pathogen.…”