TY - JOUR
T1 - Low temperature and high humidity affect dynamics of chlorophyll biosynthesis and secondary metabolites in Cucumber
AU - Amin, Bakht
AU - Atif, Muhammad Jawaad
AU - Kandegama, W. M.W.W.
AU - Nasar, Jamal
AU - Alam, Pravej
AU - Fang, Zhongming
AU - Cheng, Zhihui
N1 - Publisher Copyright:
© The Author(s) 2024.
PY - 2024/12
Y1 - 2024/12
N2 - Background: During the cold season, low temperature (LT) and high relative humidity (HRH) are significant environmental factors in greenhouses and plastic tunnels, often hindering plant growth and development. The chlorophyll (Chl) biosynthesis inhibitory mechanisms under LT and HRH stress are still widely unclear. To understand how cucumbers seedlings respond to LT and HRH stress, we investigated the impact of these stressors on Chl biosynthesis. Results: Our results revealed that individual LT, HRH and combined LT + HRH stress conditions affected chlorophyll a, b, total chlorophyll and carotenoid content, reducing the levels of these pigments. The levels of Chlorophyll precursors were also markedly reduced under LT and HRH stresses, with the greatest reduction observed in cucumber seedlings exposed to LT + HRH conditions (9/5℃, 95%HRH). The activities of glutamate-1-semialdehyde transaminase (GSA-AT), ALA dehydratase (ALAD), Mg-chelatase, and protochlorophyllide oxidoreductase (POR) were increased under individual LT, HRH, conditions but decreased by combination of LT + HRH stress condition. In addition, Chl biosynthesis related genes (except PBG) were upregulated by the HRH stress but were significantly downregulated under the LT + HRH stress condition in cucumber seedlings. Furthermore, the content of phenols, flavonoids and phenolic acids (cinnamic acid and caffeic acid) were significantly surged under LT + HRH treatment over the control. Histochemical observation showed higher O2− and H2O2 content in cucumber leaves during the LT and HRH stress. Conclusion: The results indicate that LT + HRH stress significantly impairs chlorophyll biosynthesis in cucumber seedlings by drastically reducing pigment accumulation, altering enzyme activity and gene expression. Additionally, LT + HRH stress induces oxidative damage, which further exacerbates the decline in chlorophyll content and affects overall cucumber metabolism.
AB - Background: During the cold season, low temperature (LT) and high relative humidity (HRH) are significant environmental factors in greenhouses and plastic tunnels, often hindering plant growth and development. The chlorophyll (Chl) biosynthesis inhibitory mechanisms under LT and HRH stress are still widely unclear. To understand how cucumbers seedlings respond to LT and HRH stress, we investigated the impact of these stressors on Chl biosynthesis. Results: Our results revealed that individual LT, HRH and combined LT + HRH stress conditions affected chlorophyll a, b, total chlorophyll and carotenoid content, reducing the levels of these pigments. The levels of Chlorophyll precursors were also markedly reduced under LT and HRH stresses, with the greatest reduction observed in cucumber seedlings exposed to LT + HRH conditions (9/5℃, 95%HRH). The activities of glutamate-1-semialdehyde transaminase (GSA-AT), ALA dehydratase (ALAD), Mg-chelatase, and protochlorophyllide oxidoreductase (POR) were increased under individual LT, HRH, conditions but decreased by combination of LT + HRH stress condition. In addition, Chl biosynthesis related genes (except PBG) were upregulated by the HRH stress but were significantly downregulated under the LT + HRH stress condition in cucumber seedlings. Furthermore, the content of phenols, flavonoids and phenolic acids (cinnamic acid and caffeic acid) were significantly surged under LT + HRH treatment over the control. Histochemical observation showed higher O2− and H2O2 content in cucumber leaves during the LT and HRH stress. Conclusion: The results indicate that LT + HRH stress significantly impairs chlorophyll biosynthesis in cucumber seedlings by drastically reducing pigment accumulation, altering enzyme activity and gene expression. Additionally, LT + HRH stress induces oxidative damage, which further exacerbates the decline in chlorophyll content and affects overall cucumber metabolism.
KW - Chlorophyll biosynthesis
KW - Cucumis sativus
KW - Gene expression
KW - High humidity
KW - Low temperature
KW - Secondary metabolites
UR - http://www.scopus.com/inward/record.url?scp=85205446711&partnerID=8YFLogxK
U2 - 10.1186/s12870-024-05615-2
DO - 10.1186/s12870-024-05615-2
M3 - Article
C2 - 39350005
AN - SCOPUS:85205446711
SN - 1471-2229
VL - 24
JO - BMC Plant Biology
JF - BMC Plant Biology
IS - 1
M1 - 903
ER -