Genetic Diversity and Population Structure of Moroccan Isolates Belong to Alternaria spp. Causing Black Rot and Brown Spot in Citrus.

Lamyaa Zelmat,Joseph Mbasani Mansi,Mohammed Ibriz,Rachid Mentag,Slimane Khayi,Fatima Gaboun,Sarra Aouzal,Mohammed El Guilli,Antonio Ferrante

doi:10.1155/2021/9976969

Abstract

Alternaria alternata is one of the most important fungi causing various diseases on citrus worldwide. In Morocco, Alternaria black rot (ABR) and Alternaria brown spot (ABS) are two major diseases causing serious losses in commercial cultivars of citrus. The aim of the present work was to study the genetic diversity and the population structure of isolates belonging to sect. Alternaria obtained from infected citrus fruits, collected from seven provinces at different locations in Morocco (markets, packinghouses, and orchards). Forty-five isolates were analyzed by sequence-related amplified polymorphism (SRAP) markers, and cluster analysis of DNA fragments was performed using UPGMA method and Jaccard coefficient. Cluster analysis revealed that isolates were classified in four distinct groups. AMOVA revealed also a large extent of variation within sect. Alternaria isolates (99%). The results demonstrate that no correlation was found among SRAP pattern, host, and geographical origin of these isolates. Population structure analyses showed that the Alternaria isolates from the same collection origin had almost a similar level of admixture.

Highlights

Citrus (Citrus spp., Rutaceae) is one of the most important crops due to its high annual worldwide production
AMOVA results demonstrate that the level of genetic diversity was higher within the Moroccan Alternaria populations (99%) than among them (1%)
Cluster analysis constructed according to the genetic diversity of the isolates and their distribution generated four distinct groups

Summary

Introduction

Citrus (Citrus spp., Rutaceae) is one of the most important crops due to its high annual worldwide production. Citrus are widely cultivated in over 140 countries around the world [2]. According to USDA [3], Morocco is one of three major producing countries of citrus in the Mediterranean region due to its favorable weather and increased acreage. In 2019, the Moroccan citrus cultivation area reached more than 129,000 ha generating a total production of 2.6 Mt [4]. This crop is constantly threatened by fungal diseases that cause significant losses either in the field or after harvest leading to important economic impacts

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