Affiliation:
1. Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Agricultural College of Yangzhou University, Yangzhou 225009, China
2. Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
Abstract
In maize (Zea mays), the disease known as “top rot” causes necrosis of the upper plant, disrupts tassel formation and pollen dispersal, and decreases yield. However, the causal agent, mode of pathogen infestation, and genetic architecture of resistance in maize remain to be explored. Here, to identify the causal agent, we isolated 41 fungal strains from maize plants infected with top rot. We classified these strains into six groups based on their morphological and molecular characteristics. Four species of Fusarium (F. fujikuroi, F. equiseti, F. proliferatum, and F. verticillioides) were able to cause top rot, with F. fujikuroi and F. equiseti being the main causal agents. Microscopic observations of a F. fujikuroi strain labeled with enhanced green fluorescent protein revealed that this pathogen first colonizes the stomata of leaves and then spreads through intercellular spaces, creating an expanding lesion. To dissect the genetic basis of maize resistance to top rot, we performed quantitative trait locus (QTL) mapping using a recombinant inbred line population constructed from the resistant parent LDC-1 and the susceptible parent YS501. Under natural conditions in Yangzhou and Hainan, we detected three and five QTLs, respectively, with qRtr7-1, located on chromosome 7, detected in both environments. Using inoculated seedlings, we detected three QTLs for resistance on chromosomes 1, 5, and 8. These results improve our understanding of maize top rot and provide a theoretical basis for its control.
Funder
Key Research and Development Program of Jiangsu Province
Jiangsu Government
National Natural Science Foundation of China
China Postdoctoral Science Foundation
Agricultural Independent Innovation Fund of Jiangsu Province
Subject
Plant Science,Agronomy and Crop Science