TY - JOUR
T1 - Flavonone 3‐hydroxylase relieves bacterial leaf blight stress in rice via overaccumulation of antioxidant flavonoids and induction of defense genes and hormones
AU - Jan, Rahmatullah
AU - Khan, Muhammad Aaqil
AU - Asaf, Sajjad
AU - Lubna,
AU - Park, Jae Ryoung
AU - Lee, In Jung
AU - Kim, Kyung Min
N1 - Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/6/1
Y1 - 2021/6/1
N2 - Efficient accumulation of flavonoids is important for increased tolerance to biotic stress. Although several plant defense mechanisms are known, the roles of many pathways, proteins, and secondary metabolites in stress tolerance are unknown. We generated a flavanone 3‐hydroxylase (F3H) overexpressor rice line and inoculated Xanthomonas Oryzae pv. oryzae and compared the control and wildtype inoculated plants. In addition to promoting plant growth and developmental maintenance, the overexpression of F3H increased the accumulation of flavonoids and increased tolerance to bacterial leaf blight (BLB) stress. Moreover, leaf lesion length was higher in the infected wildtype plants compared with infected transgenics. Kaempferol and quercetin, which scavenge reactive oxygen species, overaccumulated in transgenic lines compared with wildtypes in response to pathogenic infection, detected by scanning electron microscopy and spectrophotometry. The induction of F3H altered the antioxidant system and reduced the levels of glutathione peroxidase activity and malondialdehyde (MDA) contents in the transgenic lines compared with the wildtypes. Downstream gene regulation analysis showed that the expression of F3H increased the regulation of flavonol synthase (FLS), dihydroflavonol 4‐reductase (DFR), and slender rice mutant (SLR1) during BLB stress. The analysis of SA and JA signaling revealed an antagonistic interaction between both hormones and that F3H induction significantly promoted SA and inhibited JA accumulation in the transgenic lines. SA‐dependent nonexpressor pathogenesis‐related (NPR1) and Xa1 showed significant upregulation in the infected transgenic lines compared with the infected control and wildtype lines. Thus, the overexpression of F3H was essential for increasing BLB stress tolerance.
AB - Efficient accumulation of flavonoids is important for increased tolerance to biotic stress. Although several plant defense mechanisms are known, the roles of many pathways, proteins, and secondary metabolites in stress tolerance are unknown. We generated a flavanone 3‐hydroxylase (F3H) overexpressor rice line and inoculated Xanthomonas Oryzae pv. oryzae and compared the control and wildtype inoculated plants. In addition to promoting plant growth and developmental maintenance, the overexpression of F3H increased the accumulation of flavonoids and increased tolerance to bacterial leaf blight (BLB) stress. Moreover, leaf lesion length was higher in the infected wildtype plants compared with infected transgenics. Kaempferol and quercetin, which scavenge reactive oxygen species, overaccumulated in transgenic lines compared with wildtypes in response to pathogenic infection, detected by scanning electron microscopy and spectrophotometry. The induction of F3H altered the antioxidant system and reduced the levels of glutathione peroxidase activity and malondialdehyde (MDA) contents in the transgenic lines compared with the wildtypes. Downstream gene regulation analysis showed that the expression of F3H increased the regulation of flavonol synthase (FLS), dihydroflavonol 4‐reductase (DFR), and slender rice mutant (SLR1) during BLB stress. The analysis of SA and JA signaling revealed an antagonistic interaction between both hormones and that F3H induction significantly promoted SA and inhibited JA accumulation in the transgenic lines. SA‐dependent nonexpressor pathogenesis‐related (NPR1) and Xa1 showed significant upregulation in the infected transgenic lines compared with the infected control and wildtype lines. Thus, the overexpression of F3H was essential for increasing BLB stress tolerance.
KW - Antagonistic
KW - Antioxidant
KW - Bacterial leaf blight
KW - Kaempferol
KW - Malondialdehyde
UR - http://www.scopus.com/inward/record.url?scp=85107289493&partnerID=8YFLogxK
U2 - 10.3390/ijms22116152
DO - 10.3390/ijms22116152
M3 - Article
C2 - 34200345
AN - SCOPUS:85107289493
SN - 1661-6596
VL - 22
JO - International Journal of Molecular Sciences
JF - International Journal of Molecular Sciences
IS - 11
M1 - 6152
ER -