Content Description

Late leaf spot (LLS), caused by Nothopassalora personata, is a destructive foliar disease ofpeanut (Arachis hypogaea L.) that significantly reduces both yield and quality. The assessments of disease resistance primarily rely on visible symptoms, which usually appear in the later stages of infection. This study aimed to evaluate differences in photosynthetic efficiency and reactive oxygen species (ROS) production under pathogen stress as a potential diagnostic tool for early indicators of resistance. Two peanut genotypes, Georgia-13M (G-13M) (susceptible) and CB-7 (resistant) were assessed at multiple days: 1, 3, 5, 7, 12, and 18 days after inoculation [dai]). Chlorophyll fluorescence analysis (Pulse-Amplitude Modulation [PAM]) fluorometry was used to measure the efficiency of photosystem II (Qymax), and quantitative measurements of ROS, specifically hydrogen peroxide (H₂O₂), was used quantify ROS accumulation. The results showed that CB-7 maintained significantly higher photosynthetic efficiency compared to G-13M at 18 dai (p < 0.0001), indicating a better preservation of photosynthetic function under disease pressure. CB-7 also exhibited significantly greater H₂O₂ accumulation at 18 dai (p < 0.0001), which likely correlate with enhanced defense responses. Phenotypic assessments further supported these findings, with G-13M showing a higher number of lesions than CB-7 at 18 dai (p < 0.0001), with lesions first appearing at 9 dai in G-13M and 11 dai in CB-7. No significant differences were found between the genotypes in lesion size (p = 0.0661) or the percentage of sporulating lesions (p = 0.1287) at 18 dai. These findings indicate that CB-7 maintains better photosynthetic performance and higher levels of ROS than G-13M during the later stages of infection. This suggests that CB-7 might use ROS to trigger its defense system and help fight off the disease. Photosynthetic efficiency and ROS dynamics may aid in breeding disease-resistant peanuts, supporting sustainable production with less chemical use.

Acquisition Type

Deposit

Provenance

Asiedu, Emmanuel

Restrictions Apply

No

Use Restrictions

Embargoed at author's request until 2027-08-06.