Deciphering Maize Resistance to Late Wilt Disease Caused by Magnaporthiopsis maydis: Agronomic, Anatomical, Molecular, and Genotypic Insights

Walaa R. Abdelghany^1*Mohsen M. Elsharkawy²Ramy N. F. Abdelkawy³Reda I Omara¹Khaled Abdelaal²Abeer H Abass¹Wael Nabil Hozzein⁴Tarek Eisa¹Dalal Hussain ALkhalifah⁵Ayman H. Abou Tabl⁶

• ¹Plant Pathology Research Institute, Agricultural Research Center, Giza, Egypt., Giza, Egypt
• ²Department of Agricultural Botany, Faculty of Agriculture, Kafrelsheikh University, Kafr Elsheikh, Kafr el-Sheikh, Egypt
• ³Central Lab. For Design and Stat. Anal. Res., ARC, Giza, Egypt
• ⁴Department of Botany and Microbiology, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
• ⁵Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
• ⁶Department of Plant Pathology, Faculty of Agriculture, Mansoura universiy, Mansoura, Egypt

Magnaporthiopsis maydis, the causal agent of late wilt disease (LWD), poses a significant threat to maize production by reducing grain yield and quality. This study evaluated the responses of fifteen maize genotypes to LWD across three growing seasons at two research stations: Gemmeiza and Sids. The investigation encompassed disease incidence (DI%), yield components, enzymatic activities, anatomical traits, and molecular responses. Combined analysis of variance revealed significant effects (p < 0.05) of genotype, environment, and genotype × environment interaction (GEI). The additive main effects and multiplicative interaction (AMMI) model demonstrated significant GEI effects for DI% and hundred kernel weights. The disease parameters of maize genetic resistance to LWD, DI%, AUDPC, rAUDPC, CARPA, and RRI demonstrated that genotypes TWC1100, SC30K9, and SC2031 showed low disease incidence and a high RRI of more than 8.3 average for both locations. Conversely, the check cultivar Boushy recorded the highest DI% and lowest RRI. Genotypes TWC1100 and SC30K9 achieved the highest mean kernel weight at Gemmeiza (42.8 g and 41.5 g, respectively). The AMMI stability value (ASV) analysis indicated that TWC1100, SC30K9, TWC324, and SC130 were the most stable genotypes. Overall, SC2031, SC2055, and TWC1100 were the top performers for yield traits. Resistant genotypes showed increased peroxidase activity, while susceptible ones exhibited higher electrolyte leakage. Anatomical analysis revealed superior root structure in SC2031. RT-quantitative PCR analysis showed that PR1 and PR4 genes displayed pathogen-specific expression patterns and responded differently in maize genotypes. The TWC1100 genotype showed the best results after infection, while Boushy genotype exhibited limited expression of PR1 and PR4 genes. These findings underscore the potential of breeding programs to develop LWD-resistant and high-yielding maize genotypes tailored to specific environments.