The Journal of Plant Pathology Editors
’ Choice November 2020
# Società Italiana di Patologia Vegetale (S.I.Pa.V.) 2020
We are pleased to introduce eight papers selected for the Editors’ Choice section of the current issue of the Journal of Plant Pathology. The topics covered by these papers are ex-tremely diverse, and equally diverse are the nations in which the studies were conducted. Here are the selections for fungal diseases: a novel eco-friendly control of leaf blast was suc-cessfully tested in India; ecological aspects of an important but neglected disease of ornamentals was elucidated for the first time in Mexico; late blight of potato was first reported and studied in Oman; and the physiological impacts of a biotrophic pathogen were studied in China. For bacterial and phytoplasma diseases, the Editors were impressed by the first study on Ralstonia in Mali; by a study furthering the under-standing of the interaction between a bacterium and its host’s chloroplast; and by a thorough study of the genetic variability and coevolution of a pathogen of olive trees and its hosts in the Mediterranean region. Finally, a study analyzing the diversity of badnaviruses infecting banana in southern China is the last pick for this issue’s Editor’ Choice section.
In “Silicon (Si) enhances the resistance in finger millet genotypes against blast disease” by Jadhao and Rout (india), a significant negative correlation was observed between sili-con accumulation in the plants (leaf, stem, and root) and per-cent disease index, providing an alternative eco-friendly dis-ease management strategy. Silicon accumulation was also de-pendent on plant genotype, further suggesting that preselec-tion of certain plant lines combined with silicon treatment may provide an excellent disease control strategy. In“Temporal progress of roselle leaf and calyx spot disease in Guerrero, Mexico” by Ortega-Acosta et al. (Mexico) results identify the ideal temperature and relative humidity for progression of disease in flowers of hibiscus caused by the pathogen Corynespora cassiicola. The authors were also able to find a strong correlation between disease severity in leaves and flowers, thus providing important disease predictive informa-tion in a little studied, but economically important, plant path-ogen. The infamous late blight of potato pathogen was iden-tified for the first time in Oman by Al-Kaabi et al. (Oman, USA) in“Appearance and diversity of Phytophthora infestans in Oman in 2013-2015”. In their paper, the authors describe
how a genetic and phenotypic analysis of several isolates of the pathogen identified the presence of multiple genotypes and of variable resistance to the chemical mefenoxam, even when comparing different isolates belonging to the same genotype. This finding underlines how history of an isolate may be equal-ly or more important than genetic background, when dealing with a plant pathogen. The study titled“Photosynthetic proper-ties and biochemical metabolism of Cucurbita moschata genotypes following infection with powdery mildew” by Chen et al. (China) attracted our attention because it pro-vides an insight into the effects of a biotrophic pathogen on its host. In spite of its epiphytic growth, Podosphaera xanthii caused both a decrease of photosynthesis and an upregulation of secondary metabolic pathways normally associated with plant defenses. The ability to maintain suf-ficiently high photosynthetic levels and to induce high ex-pression of defense related enzymes was associated with lower susceptibility in pumpkin plants.
“Identification and characterization of Ralstonia spp. caus-ing bacterial wilt disease of vegetables in Mali” by Bihon et al. (Mali, Taiwan) describes one of the first surveys in Mali on this important pathogen. Thanks to their strong design, the authors identified for the first time both Ralstonia solanacearum and R. pseudosolanacearum from three impor-tant vegetable hosts. The study“Determination of the role of HrpN effector protein, as a key factor in course of interaction between Erwinia amylovora with chloroplasts of pear” by Taheri Shahrestani et al. (Iran) has been selected as editor’s choice because it provides an in depth insight on the surpris-ingly important role of some effectors in the pathogenesis of fire blight, more specifically of their effect on chloroplasts. Rahi et al. (Italy) used a state-of-the-art molecular analysis (MLVA, Multiple Loci Variable number of tandem repeat Analysis) as an efficient genotyping technique to study genet-ic variation of P. savastanoi occurring on different hosts. In the paper titled“Genetic diversity and population structure of Pseudomonas savastanoi, an endemic pathogen of the Mediterranean area, revealed up to strain level by the MLVA assay”, the authors could demonstrate that a long co-evolution of host and pathogen can lead to the
https://doi.org/10.1007/s42161-020-00691-3
Published online: 26 October 2020
development of very closely related, though different, geno-types occurring in one location or even the same plant.
Finally, the paper“Genetic diversity analysis reveals new badnaviruses infecting banana in South China” by Rao et al. (China) sheds new light on the diversity of the badnaviruses infecting banana. Banana streak is a disease of major significance for banana crops worldwide and is reg-ulated or considered of quarantine significance in a number of countries. While banana streak virus (BSV, genus Badnavirus, family Caulimoviridae) was initially identified as the causal agent, the large diversity of badnaviruses in-fecting banana has led some years ago to the splitting of BSV into several distinct species. In addition, symptoms caused by the sugarcane bacilliform virus on banana are also notoriously similar to those caused by BSV. Using a published broad spectrum PCR assay, followed by the clon-ing and sequencclon-ing of amplicons, the authors have analyzed the diversity of badnaviruses infecting banana in southern
China. The carefully performed study highlights a large vi-ral diversity of BSV, but also provides the first report of infection of banana by sugarcane bacilliform Guadeloupe A virus, and possibly of a further- yet to be classified- viral species. Besides increasing our knowledge on the distribu-tion and diversity of banana-infecting badnaviruses, this interesting paper may have significant regulatory and diag-nostic implications.
Congratulation to all the authors of the above papers for their significant scientific contribution to the field of Plant Pathology.
Matteo Garbelotto, (Editor in Chief), Luisa Rubino (Managing Editor), Thierry Candresse, Jaap Janse and Paolo Gonthier (Senior Editors)
Publisher’s note Springer Nature remains neutral with regard to jurisdic-tional claims in published maps and institujurisdic-tional affiliations.
