The Rhizoctonia solani AG1-IB (isolate 7/3/14) transcriptome during interaction with the host plant lettuce (Lactuca sativa L.)

Abstract

The necrotrophic pathogen Rhizoctonia solani is one of the most economically important soil-borne pathogens of crop plants. Isolates of R. solani AG1-IB are the major pathogens responsible for bottom-rot of lettuce (Lactuca sativa L.) and are also responsible for diseases in other plant species. Currently, there is lack of information regarding the molecular responses in R. solani during the pathogenic interaction between the necrotrophic soil-borne pathogen and its host plant. The genome of R. solani AG1-IB (isolate 7/3/14) was recently established to obtain insights into its putative pathogenicity determinants. In this study, the transcriptional activity of R. solani AG1-IB was followed during the course of its pathogenic interaction with the host plant lettuce under controlled conditions. Based on visual observations, three distinct pathogen-host interaction zones on lettuce leaves were defined which covered different phases of disease progression on tissue inoculated with the AG1-IB (isolate 7/3/14). The zones were defined as: Zone 1—symptomless, Zone 2—light brown discoloration, and Zone 3—dark brown, necrotic lesions. Differences in R. solani hyphae structure in these three zones were investigated by microscopic observation. Transcriptional activity within these three interaction zones was used to represent the course of R. solani disease progression applying high-throughput RNA sequencing (RNA-Seq) analysis of samples collected from each Zone. The resulting three transcriptome data sets were analyzed for their highest expressed genes and for differentially transcribed genes between the respective interaction zones. Among the highest expressed genes was a group of not previously described genes which were transcribed exclusively during early stages of interaction, in Zones 1 and 2. Previously described importance of up-regulation in R. solani agglutinin genes during disease progression could be further confirmed; here, the corresponding genes exhibited extremely high transcription levels. Most differentially higher expressed transcripts were found within Zone 2. In Zone 3, the zone with the strongest degree of interaction, gene transcripts indicative of apoptotic activity were highly abundant. The transcriptome data presented in this work support previous models of the disease and interaction cycle of R. solani and lettuce and may influence effective techniques for control of this pathogen.

Comparative Transcriptome Analysis Provides Molecular Insights into the Interaction of Beet necrotic yellow vein virus and Beet soil-borne mosaic virus with Their Host Sugar Beet

“…The total RNA was then purified using the Direct-zol RNA Miniprep Plus (Zymo Research, Orange, CA, USA) following the manufacturer's instructions. Dual cDNA libraries were prepared, sequenced and analysed as recently described [33] with smaller modifications. In brief, 2.25 µg of RNA per sample was used for preparation of stranded libraries with the TruSeq mRNA Sample Preparation Kit (Illumina Inc., San Diego, CA, USA).…”

Volatile Organic Compounds From Lysobacter capsici AZ78 as Potential Candidates for Biological Control of Soilborne Plant Pathogens

“…As a result, regulations become stricter and some synthetic chemical pesticides have been already banned, as in the case of methyl bromide (2011/120/EU). This pesticide was constantly used in soil fumigation for the control of the soilborne phytopathogenic microorganisms Pythium ultimum, Rhizoctonia solani and Sclerotinia minor, responsible for a plethora of commercially significant plant diseases (Ah-Fong et al, 2017;Verwaaijen et al, 2017;Crutcher et al, 2018). Considering their life cycle, it is undeniable that soil fumigation is an effective way for managing soilborne phytopathogenic microorganisms.…”

Biosynthesis of Oxylipins by Rhizoctonia solani with Allene Oxide and Oleate 8S,9S‐Diol Synthase Activities

“…Transcriptome analysis of R. solani AG1‐1B during plant infection has now been published (Verwaaijen et al, ; Wibberg et al, ). These studies may provide information on the expression of the three tentative enzymes of the LDS family during plant infection and their biological significance.…”

“…R. solani can be divided into at least 13 anastomosis groups (AG) based on the fusions of hyphae between different isolates and further into subgroups based on the host range (Okubara et al, ; Wibberg et al, ). The draft genome sequence of R. solani AG1‐1 (A and B), AG3, AG8, and expressed sequence tags have been reported since 2014 (Verwaaijen et al, ; Wibberg et al, , , ).…”