Journal of Plant Pathology最新文献

Plant resistances impose strong selective pressure on plant pathogen populations through the deployment of resistance genes, which leads to the emergence of new virulences. The pathogen adaptation also involves other parasitic fitness traits, especially aggressiveness components. A previous study on Puccinia triticina, the causal agent of wheat leaf rust, revealed that the distribution frequency of virulences in the French pathogen population cannot be fully explained by the major resistance genes deployed in the landscape. From 2012 to 2015, two dominant pathotypes (distinguished by their combination of virulences) were equally frequent despite the theoretical advantage conferred to one pathotype (166 317 0) by its virulence to Lr3, frequent in the cultivated landscape, whereas the other (106 314 0) is avirulent to this gene. To explain this apparent contradiction, we assessed three components of aggressiveness — infection efficiency, latency period and sporulation capacity — for 23 isolates representative of the most frequent genotype within each pathotype (106 314 0-G2 and 166 317 0-G1, identified by their combination of microsatellite markers). We tested these isolates on seedlings of Michigan Amber, a ‘naive’ wheat cultivar that has never been grown in the landscape, Apache, a ’neutral‘ cultivar with no selection effect on the landscape-pathotype pattern, and several cultivars that were frequently grown. We found that 106 314 0-G2 was more aggressive than 166 317 0-G1, with a consistency for the three components of aggressiveness. Our results show that aggressiveness plays a significant role in driving evolution in pathogen populations by acting as a selective advantage, even offsetting the disadvantage of lacking virulence towards a major Lr gene. Higher aggressiveness represents a competitive advantage that is likely even more pronounced when exhibited at the landscape scale as the expression of its multiple components is amplified by the polycyclic nature of epidemics.

The partitivirids feature an icosahedral protein coating accommodating both their dsRNA genome and RNA-dependent RNA polymerase (RdRP). This signifies that transcription and replication activities of the viral polymerase occur within the capsid, emphasizing that the viral cycle relies on polymerase incorporation. Particles lacking RdRP are defective and hence non-infectious. Encapsidation and replication are intricately linked for dsRNA viruses, to the extent that, for many of these, such as the cystovirids, the RdRP serves a dual role as a transcriptase/replicase and a pro-assembly factor, ensuring structural stability and overall capsid integrity. This work investigates if RdRP has a similar role within the capsid of Cannabis cryptic virus (CanCV), a betapartitivirus affecting Cannabis sativa. Utilizing reverse genetics in Nicotiana benthamiana, we conclusively established that RdRP expression is indispensable for CanCV’s virus-like particle formation. This study enhances our understanding of CanCV encapsidation, with RdRP serving a pivotal role as a pro-assembly factor. These preliminary findings contribute to the knowledge of viral assembly within the Partitiviridae family.

This paper describes the experience of teaching plant pathology in Italy and traces the teaching environment over a period of more than 45 years, split into three main periods: 1975–2000; 2001–2020; and after 2020. The three periods are marked by different attitudes towards agriculture and, consequently, by a variable attractiveness of agricultural study programmes for students, as well as significant changes in the population of teachers and students. The teaching experience has been described by focusing on the changes that have taken place, from the perspectives of both students and teachers, all considered in an environment of continuous transformation. The changing importance of agriculture, the different approaches of people (consumers) towards agriculture, and how it has influenced students’ choices are considered. Data related to student enrolment at the College of Agriculture of the University of Turin have been used to provide real figures, which are useful to obtain a better understanding of the changes in the student population, also considering the different attractiveness of Agricultural Sciences, Forestry and Food Science, as well as the variations in the composition of the female student population, which increased from 28% in the late 1970’s to 38% in 2020. Female students now show the highest interest in Food Science Courses. The changes in the students and teachers’ backgrounds and attitudes, as well as in the teaching and learning methods are considered, and some critical considerations are drawn, also on the basis of the developed personal experience. Moreover, the effects of the Covid-19 pandemic disruption are discussed.

Basil Downy Mildew (BDM), caused by the oomycete Peronospora belbahrii, is a major issue for sweet basil (Ocimum basilicum L.) production worldwide. Currently, the disease is mainly controlled by chemical fungicides, but the development of populations of the pathogen which are resistant to the most widely used compounds is leading to the research of alternative crop protection strategies. Therefore, in this paper, some cropping variables were tested in a field trial conducted in two consecutive years (2021 and 2022) in Northern Italy in organic farming conditions, with the overall objective to optimize basil productivity and quality and limit BDM occurrence. These include two basil varieties, two sowing densities (dense, 30 kg/ha, and sparse, 15 kg/ha), and two irrigation systems (drip and sprinkler). A higher incidence and severity of BDM in 2022 compared to 2021 was observed, mainly due to the different climatic conditions that occurred in the two years. Year 2022 was characterized by high temperatures and repeated drought phenomena that led to basil stress and BDM severe outbreak. Moreover, variety 1 (considered resistant to P. belbahrii) was confirmed to be completely resistant in 2021 but it was found to be susceptible the following year, with disease incidence and severity comparable to variety 2 (medium susceptible). No differences were detected in terms of BDM occurrence and crop yield between the two sowing densities (mean of 58.4% and 26.6% of BDM incidence and severity, respectively; mean yield 1.4 kg/m²), while it emerged that drip irrigation can be useful in reducing BDM (−23.1% BDM severity). Therefore, this study suggests that the crop protection strategies tested, even if not definitive solutions, can significantly contribute to manage BDM more effectively, while preserving basil productivity and quality.

Plants face numerous challenges in their ongoing battle against pests and diseases. Traditional protection methods often involve synthetic pesticides, which have a detrimental impact on the environment and human health. However, the quest for eco-friendly and sustainable solutions has brought surfactin into the spotlight as a promising defender of plants. Surfactin, a biometabolite produced by Bacillus spp., has gained attention due to its multifaceted properties contributing to plant defense. This review highlights the eco-friendly nature of surfactin and explores its notable functions as an antimicrobial agent, the ability to modulate plant defense mechanisms, enhance colonization and biofilm formation of antagonists, and ultimately promote plant growth. Furthermore, the environmentally friendly characteristics of surfactin, such as its biodegradability and low toxicity, make it an ideal candidate for sustainable plant protection strategies. The potential applications and challenges in utilizing surfactin as an eco-friendly defender of plants are discussed, providing insights for future research and the development of innovative and sustainable agricultural practices.