Clarification on Host Range of Didymella pinodes the Causal Agent of Pea Ascochyta Blight

Abstract

Didymella pinodes is the principal causal agent of ascochyta blight, one of the most important fungal diseases of pea (Pisum sativum) worldwide. Understanding its host specificity has crucial implications in epidemiology and management; however, this has not been clearly delineated yet. In this study we attempt to clarify the host range of D. pinodes and to compare it with that of other close Didymella spp. D. pinodes was very virulent on pea accessions, although differences in virulence were identified among isolates. On the contrary, studied isolates of D. fabae, D. rabiei, and D. lentil showed a reduced ability to infect pea not causing macroscopically visible symptoms on any of the pea accessions tested. D. pinodes isolates were also infective to some extend on almost all species tested including species such as Hedysarum coronarium, Lathyrus sativus, Lupinus albus, Medicago spp., Trifolium spp., Trigonella foenum-graecum, and Vicia articulata which were not mentioned before as hosts of D. pinodes. On the contrary, D. lentil and D. rabiei were more specific, infecting only lentil and chickpea, respectively. D. fabae was intermediate, infecting mainly faba bean, but also slightly other species such as Glycine max, Phaseolus vulgaris, Trifolium spp., Vicia sativa, and V. articulata. DNA sequence analysis of the nuclear ribosomal internal transcribed spacer region (ITS) was performed to confirm identity of the isolates studies and to determine phylogenetic relationship among the Didymella species, revealing the presence of two clearly distinct clades. Clade one was represented by two supported subclusters including D. fabae isolates as well as D. rabiei with D. lentil isolates. Clade two was the largest and included all the D. pinodes isolates as well as Phoma medicaginis var. pinodella. Genetic distance between D. pinodes and the other Didymella spp. isolates was not correlated with overall differences in pathogenicity. Based on evidences presented here, D. pinodes is not specialized on pea and its host range is larger than that of D. fabae, D. lentil, and D. rabiei. This has relevant implications in epidemiology and control as these species might act as alternative hosts for D. pinodes.

Molecular and Morphological Characterization of Two Novel Species Collected from Soil in Korea

“…Previous studies have reported that the genus Didymella is widely distributed in field and ornamental crops, wild plants and most saprobes species are commonly found in living or dead aerial parts of herbaceous, wooden plants [8], and some act as mutualistic endophytes [34]. Didymella pinodes (formerly known Mycosphaerella pinodes) has been reported as the main causal agent of Ascochyta blight, which is one of the most important fungal diseases of the pea (Pisum sativum) worldwide [35,36]. D. tanaceti and D. rosea have been identified as plant pathogens that cause the tan spot in pyrethrum [30].…”

Insights to plant–microbe interactions provide opportunities to improve resistance breeding against root diseases in grain legumes

“…These include brown to black lesions, spreading from the upper part of the main root into the root system and the stem; discoloration of the root system; and softening and decay of the root and lower stem cortex. (Aveskamp, de Gruyter, Woudenberg, Verkley, & Crous, 2010;Baćanović-Šišić, Šišić, Schmidt, & Finckh, 2017;Barilli, Cobos, & Rubiales, 2016;Haware, 1981;Tran, You, Khan, & Barbetti, 2016).…”

“…Didymella pinodella or Phoma medicaginis var. pinodella ) and represent a threat to legume cultivations worldwide (Aveskamp, de Gruyter, Woudenberg, Verkley, & Crous, ; Baćanović‐Šišić, Šišić, Schmidt, & Finckh, ; Barilli, Cobos, & Rubiales, ; Haware, ; Tran, You, Khan, & Barbetti, ). These phytopathogenic fungi are responsible for severe leaf and stem spots and root rots on many legume host plants including pea, chickpea, lentil, and faba bean (Muehlbauer & Chen, ).…”

The Effect of Disease and Season to Hepatopancreas and Intestinal Mycobiota of Litopenaeus vannamei

“…The alteration resulted in that the number of the pathogens which should have been a normal commensal increased. For the healthy group, the number of plant-pathogenic Didymella (Barilli et al, 2016; Ranjbar Sistani et al, 2017) and Filobasidium , presented a significant increase in the gut compared with the sick groups (Figure 6A,C,D). The healthy hepatopancreas group had a significantly higher abundance of Pyrenochaetopsis than the sick hepatopancreas groups (Figure 6B,E).…”