Photosynthetic Costs and Impact on Epidemiological Parameters Associated with Ht Resistance Genes in Maize Lines Infected with Exserohilum turcicum .

Autor: Navarro BL; Georg-August-Universität Göttingen, Department of Crop Sciences, Division of Plant Pathology and Crop Protection, Göttingen, Germany., Streit S; Georg-August-Universität Göttingen, Department of Crop Sciences, Division of Plant Pathology and Crop Protection, Göttingen, Germany., Nogueira Júnior AF; BASF Digital Farming GmbH, Cologne, Germany., von Tiedemann A; Georg-August-Universität Göttingen, Department of Crop Sciences, Division of Plant Pathology and Crop Protection, Göttingen, Germany.
Jazyk: angličtina
Zdroj: Phytopathology [Phytopathology] 2024 Apr; Vol. 114 (4), pp. 760-769. Date of Electronic Publication: 2024 Apr 15.
DOI: 10.1094/PHYTO-07-23-0247-R
Abstrakt: Northern corn leaf blight, caused by Exserohilum turcicum , is mainly controlled by the use of resistant cultivars. Maize lines carrying individual resistance genes B37 Ht1 , B37 Ht2 , B37 Ht3 , and B37 Htn1 express different defense symptoms having an impact on the photosynthetic activity, the accumulation of reactive oxygen species, and epidemiological parameters. Plants were inoculated with a race 0 isolate of E. turcicum conferring a compatible interaction with B37 and incompatible interactions with plants carrying resistance genes. Five days postinoculation (dpi), the resistant lines displayed a reduction in leaf CO 2 assimilation of 30 to 80% compared with healthy plants. At 14 dpi, inoculated plants of B37 Ht1 showed a significant decrease in leaf CO 2 assimilation, similar to B37 (up to 94%). The instantaneous carboxylation efficiency was significantly reduced on inoculated plants of the lines B37 Ht2 , B37 Ht3 , and B37 Htn1 (54 to 81%) at 5 dpi. Curiously, the reduction in carboxylation efficiency for B37 and B37 Ht1 (up to 95%) was higher at 14 dpi than at 5 dpi (up to 81%). At 6 dpi, low levels of H 2 O 2 were detected in B37 Ht1 , in contrast to B37 Htn1 , where a high H 2 O 2 level and peroxidase activity were observed. The sporulation rate on B37 Ht1 , B37 Ht3 , and B37 Htn1 decreased by 92% compared with the susceptible control, whereas strong sporulation occurred in lesions on line B37 Ht2. The resistance in maize to E. turcicum conferred by Ht resistance genes is associated with photosynthetic costs and may have quite contrasting effects on host physiology and major epidemiological parameters, such as sporulation, which contributes inoculum for secondary infections.
Competing Interests: The author(s) declare no conflict of interest.
Databáze: MEDLINE
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