Identification of Rice Seed-Derived Fusarium spp. and Development of LAMP Assay against Fusarium fujikuroi

Hubiao Jiang,Na Wu,Xiaobi Wu,Bin Li,Hui Wang,Shaomin Jin,Fei Liu,Yidan Bao,Jing-Ze Zhang,Temoor Ahmed

doi:10.3390/pathogens10010001

Hubiao Jiang, Na Wu + Show 8 more

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https://doi.org/10.3390/pathogens10010001

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Journal: Pathogens	Publication Date: Dec 22, 2020
Citations: 14	License type: CC BY 4.0

Affiliation: Zhejiang University

Abstract

Fusarium species are important seedborne pathogens that cause rice bakanae disease (RBD). In this study, 421 strains were isolated from 25 rice samples collected from Zhejiang, Anhui, and Jiangxi provinces of China. Furthermore, 407 isolates were identified as F. fujikuroi (80.05% isolation frequency), F. proliferatum (8.31%), F. equiseti (5.94%), F. incarnatum (2.61%), F. andiyazi (0.95%), and F. asiaticum (0.48%) based on morphology and translation elongation factor 1-alpha (TEF1-α) gene. Phylogenetic analysis of combined sequences of the RNA polymerase II largest subunit (RPB1), RNA polymerase II second largest subunit (RPB2), TEF1-α gene, and ribosomal DNA (rDNA) internal transcribed spacer (ITS) showed that 17 representative strains were attributed to six species. Pathogenicity tests showed that representative isolates possessed varying ability to cause symptoms of bakanae on rice seedlings. Moreover, the seed germination assay revealed that six isolates had different effects, such as inhibition of seed germination, as well as seed and bud rot. The loop mediated isothermal amplification (LAMP)-based assay were developed for the detection of F. fujikuroi. According to sequences of desaturase-coding gene promoter, a species-specific marker desM231 was developed for the detection of F. fujikuroi. The LAMP assay using seeds collected from field was validated, and diagnostics developed are efficient, rapid, and sensitive.

Highlights

Rice (Oryza sativa L.) is one of the most important staple foods that feeds more than 60% of the world’s population [1]
Microconidia were abundant in false heads or shorter chains (Figure 1A), and macroconidia were relatively slender, medium length with no significant curvature, 3- to 5-septate, apical cell tapered, and basal cell poorly developed (Figure 1B), and they were identified as F. fujikuroi
If microconidia were clavate to oval with a flattened base, 0-septate and produced in abundance in long chains from monophialides (Figure 1G), macroconidia were straight to slightly curved, and apical cell was slightly curved and basal cell was pedicillate, 3- to 6-septate, mostly 3-septate (Figure 1F) and pseudochlamydospores were formed on this medium, they were identified as F. andiyazi

Summary

Introduction

Rice (Oryza sativa L.) is one of the most important staple foods that feeds more than 60% of the world’s population [1]. Rice bakanae disease (RBD) caused by seed-borne Fusarium spp. may lead to a global food crisis. The disease incidence usually ranges from 0.25% to 20% [4], even up to 40% in India [5], leading to a severe rice yield loss [6]. Species of the F. fujikuroi species complex (FFSC or fujikuroi) [7], such as F. andiyazi, F. fujikuroi, F. proliferatum, and F. verticillioides, are associated with bakanae of rice, F. fujikuroi is believed to be the core species responsible for the symptoms and was detected only in seed samples from Asia [8].

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