Understanding Root Rot Disease in Agricultural Crops

Abstract

Root rot diseases remain a major global threat to the productivity of agricultural crops. They are usually caused by more than one type of pathogen and are thus often referred to as a root rot complex. Fungal and oomycete species are the predominant participants in the complex, while bacteria and viruses are also known to cause root rot. Incorporating genetic resistance in cultivated crops is considered the most efficient and sustainable solution to counter root rot, however, resistance is often quantitative in nature. Several genetics studies in various crops have identified the quantitative trait loci associated with resistance. With access to whole genome sequences, the identity of the genes within the reported loci is becoming available. Several of the identified genes have been implicated in pathogen responses. However, it is becoming apparent that at the molecular level, each pathogen engages a unique set of proteins to either infest the host successfully or be defeated or contained in attempting so. In this review, a comprehensive summary of the genes and the potential mechanisms underlying resistance or susceptibility against the most investigated root rots of important agricultural crops is presented.

Autotoxin Rg 1 Induces Degradation of Root Cell Walls and Aggravates Root Rot by Modifying the Rhizospheric Microbiome

“…Autotoxins and pathogens accumulated in the soil aggravate root rot diseases ( 4 , 11 ). Previous studies have shown that some autotoxins inhibit the performance of the plant species that produce them and promote the growth and pathogenicity of soilborne pathogens ( 14 ).…”

“…The symptoms of root rot include soft, water-soaked, dark brown to black lesions on the roots, yellow color and wilting of leaves, causing stunted plant growth and reduced yield. Cultural, physical, biological, and chemical control methods have been used as management strategies to control root rot diseases ( 4 ). However, these control methods have only been partially successful because the pathogens and other factors are complicated.…”

Root rot a silent alfalfa killer in China: Distribution, fungal, and oomycete pathogens, impact of climatic factors and its management

“…In addition, the R. solani is a facultative parasite and can easily compete with other soil born saprophytes. In order to survive in the soil, it develops sclerotia, a long-lasting structures or propagules ( Williamson-Benavides and Dhingra, 2021 ). These nutrient-independent propagules are formed from the undifferentiated hyphae or monilioid cells.…”

“…Four important Pythium spp. such as P. ultimum , P. irregulare , P. aphanidermatum , and P. myriotylum have been reported from alfalfa fields and are the most common root rot causing pathogens in the world ( Williamson-Benavides and Dhingra, 2021 ). During 2017 and 2019, 30 to 80% of alfalfa plants in Gansu province stunted, wilted, and dried.…”

The Antifungal Activity of Ag/CHI NPs against Rhizoctonia solani Linked with Tomato Plant Health

“…Indeed, Ag NPs can be helpful in plant disease control against pathogenic fungi [14]. In a recent study, the effect of Ag NPs on R. solani groups that contaminate cotton plants was assessed [15]. Ag NPs generate reactive oxygen species (ROS), especially superoxide radicals (O −2 ) and hydroxyl radicals (OH), that destroy the cell [16].…”