Community Analysis of Culturable Sapwood Endophytes from Apulian Olive Varieties with Different Susceptibility to Xylella fastidiosa

Endophytes are symptomless fungal and/or bacterial microorganisms found in almost all living plant species. The symbiotic association with their host plants by colonizing the internal tissues has endowed them as a valuable tool to suppress diseases, stimulate growth, and promote stress resistance. In this context, the study of culturable endophytes residing the sapwood of Apulian olives might be a promising control strategy for xylem colonizing pathogens as Xylella fastidiosa. To date, olive sapwood cultivable endophytes are still under exploration; therefore, this work pursues a study of cultivable endophytes occurrence variation in the sapwood of different olive varieties under the effect of seasonality, geographical coordinates, and X. fastidiosa infection status. Our study confirms the stability of sapwood endophytic culturable communities in the resistant olive variety and presents the seasonal and geographical fluctuation of olive trees’ sapwood endophytes. It also describes the diversity and occurrence frequency of fungal and bacterial genera, and finally retrieves some of the sapwood-inhabiting fungal and bacterial isolates, known as biocontrol agents of plant pathogens. Thus, the potential role of these bacterial and fungal isolates in conferring olive tree protection against X. fastidiosa should be further investigated

Community Analysis of Culturable Sapwood Endophytes from Apulian Olive Varieties with Different Susceptibility to <i>Xylella fastidiosa</i>

Endophytes are symptomless fungal and/or bacterial microorganisms found in almost all living plant species. The symbiotic association with their host plants by colonizing the internal tissues has endowed them as a valuable tool to suppress diseases, stimulate growth, and promote stress resistance. In this context, the study of culturable endophytes residing the sapwood of Apulian olives might be a promising control strategy for xylem colonizing pathogens as Xylella fastidiosa. To date, olive sapwood cultivable endophytes are still under exploration; therefore, this work pursues a study of cultivable endophytes occurrence variation in the sapwood of different olive varieties under the effect of seasonality, geographical coordinates, and X. fastidiosa infection status. Our study confirms the stability of sapwood endophytic culturable communities in the resistant olive variety and presents the seasonal and geographical fluctuation of olive trees’ sapwood endophytes. It also describes the diversity and occurrence frequency of fungal and bacterial genera, and finally retrieves some of the sapwood-inhabiting fungal and bacterial isolates, known as biocontrol agents of plant pathogens. Thus, the potential role of these bacterial and fungal isolates in conferring olive tree protection against X. fastidiosa should be further investigated

Advanced methods of plant disease detection. A review

International audiencePlant diseases are responsible for major economic losses in the agricultural industry worldwide. Monitoring plant health and detecting pathogen early are essential to reduce disease spread and facilitate effective management practices. DNA-based and serological methods now provide essential tools for accurate plant disease diagnosis, in addition to the traditional visual scouting for symptoms. Although DNA-based and serological methods have revolutionized plant disease detection, they are not very reliable at asymptomatic stage, especially in case of pathogen with systemic diffusion. They need at least 1–2 days for sample harvest, processing, and analysis. Here, we describe modern methods based on nucleic acid and protein analysis. Then, we review innovative approaches currently under development. Our main findings are the following: (1) novel sensors based on the analysis of host responses, e.g., differential mobility spectrometer and lateral flow devices, deliver instantaneous results and can effectively detect early infections directly in the field; (2) biosensors based on phage display and biophotonics can also detect instantaneously infections although they can be integrated with other systems; and (3) remote sensing techniques coupled with spectroscopy-based methods allow high spatialization of results, these techniques may be very useful as a rapid preliminary identification of primary infections. We explain how these tools will help plant disease management and complement serological and DNA-based methods. While serological and PCR-based methods are the most available and effective to confirm disease diagnosis, volatile and biophotonic sensors provide instantaneous results and may be used to identify infections at asymptomatic stages. Remote sensing technologies will be extremely helpful to greatly spatialize diagnostic results. These innovative techniques represent unprecedented tools to render agriculture more sustainable and safe, avoiding expensive use of pesticides in crop protection