Seed Infection Rate, but Not Pathogen Titer, Positively Correlates with Disease Index of Cephalosporium Stripe in Winter Wheat

• Published in: Phytopathology 2023-03, Vol.113 (3), p.436-447
• Main Authors: Sheng, Hongyan, Klos, Kathy L E, Murray, Timothy D
• Format: Article
• Language: English
• Subjects: Acremonium - genetics; Plant Diseases - genetics; Real-Time Polymerase Chain Reaction - methods; Seeds; Triticum - genetics
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/PHYTO-06-22-0211-R

survives primarily in colonized plant residue but is also transmitted by seed at a low frequency. The purpose of this study was to correlate disease intensity in the field with percentage of infected seed and amount of pathogen DNA using a high-throughput PCR method. Field-grown seed of three wheat cultivars was collected over 4 years from plots with a known disease index. The culture-based seed infection rate was determined by isolation of . from 2,016 seeds per seed lot. DNA of 380 seeds from each seed lot was extracted individually, and a PCR assay with a fluorescent-labeled forward primer for detecting was performed on each seed. was isolated from 0.12% of the seed on average (range 0 to 0.74%), whereas it was detected in 3.7% on average (range 1.3 to 7.6%) using PCR detection. The single-seed PCR assay was more sensitive than either the culture-based method or conventional PCR. DNA of 674 seeds that tested positive by this PCR was quantified using a real-time PCR with newly designed primers for the amount of pathogen per seed. Seed contained 0.017 to 77.1 pg/seed of DNA (mean 3.0 pg/seed). Disease index was positively correlated with seed infection rate but not with pathogen titer in seed. This fluorescent-labeled PCR, along with quantitative PCR, improved our understanding of seed transmission of . in wheat.