Research articles
ScienceAsia 47 (2021):ID 178-186 |doi:
10.2306/scienceasia1513-1874.2021.026
Aspergillus flavus virulence in pods and seeds of peanut
with different drought responsive genotypes related to
water status
Waraluk Senakoona, Suporn Nuchadomronga,*, Pornpimol Jearranaiprepameb, Gulsiri Senawonga,
Sanun Jogloyc,d, Patcharin Songsric
ABSTRACT: Drought resistance traits are important for resistance to preharvest aflatoxin contamination in peanut
seeds caused by Aspergillus flavus; however, the evidence has been controversial. The problem might be solved by
investigating fungal activities relevant to drought effects on the early pod. Herein, drought impacts on three peanut
cultivars with different genotypes were shown as leaf adaptation to reduce transpiration. High impacts were observed
in ICGV 98300, ICGV 98308, and Tainan 9 cultivars. Fungal ingress was not histologically found across sclerenchyma
to the inner parenchyma of R3 pod pericarp regardless of genotypes or water conditions. Similar activities occurred
in R5 pods of non-drought stressed control plants, and the fungus was not detectable inside newly developing seeds.
Healthy sclerenchyma likely displayed a physical barrier role. Drought led to the fungal detection in seeds of the three
cultivars. The results corresponded to the fungal germination tests in mature seeds, where A. flavus was found, of
stressed plants. A. flavus nor-1 transcript was occasionally detected showing A. flavus colonization in a number of R5
kernels of control plants. Under drought condition, the nor-1 expression was increased by 2.5 folds in Tainan 9 and
ICGV 98300, and a small increase was observed in ICGV 98308. The reducing sugar contents in R5 kernels of Tainan
9 and ICGV 98300 were also increased, suggesting the stimulation of oxidative stress and aflatoxin synthesis. High
A. flavus virulence, based on nor-1 expression and reducing sugar content, was remarkable in ICGV 98308 under water
regimes for control and drought-stressed plants under greenhouse conditions.
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| a |
Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002 Thailand |
| b |
Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002 Thailand |
| c |
Department of Agronomy, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002 Thailand |
| d |
Peanut and Jerusalem Artichoke Improvement for Functional Food Research Group and Plant Breeding
Research Center for Sustainable Agriculture, Khon Kaen University, Khon Kaen 40002 Thailand |
* Corresponding author, E-mail: suporn@kku.ac.th
Received 6 Jun 2020, Accepted 30 Jan 2021
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