The maize low-lignin mutant F2bm3 shows pleiotropic effects on photosynthetic and cell wall metabolisms in response to chilling - Université de Picardie Jules Verne Accéder directement au contenu
Poster De Conférence Année : 2019

The maize low-lignin mutant F2bm3 shows pleiotropic effects on photosynthetic and cell wall metabolisms in response to chilling

Michelle Lequart
Françoise Fournet
Jean-Marc Domon

Résumé

Maize (Zea mays L.) is one of the major crops in the world and is highly sensitive to low temperature due to its tropical origin. Chilling may particularly affect maize during early seedling growth by altering physiological processes including photosynthesis and cell wall properties, leading to biomass reduction. Changes in photosynthetic and cell wall metabolisms were investigated during a long chilling exposure in a low-lignin maize mutant, brown midrib3 (bm3), which contains a null-mutation in the gene encoding caffeic acid O-methyltransferase (COMT). Wild-type F2 plants and the near-isogenic F2 bm3 mutant were grown during 60 days with a day/night temperature regime of 15°C/11°C in a greenhouse. Photosynthetic pigments, non-structural sugars, cell wall sugars, lignin, cell wall bound hydroxycinnamic acids (HCA) contents and phenylpropanoid pathway enzyme activities were determined when the 4th leaf had fully emerged. Results showed that the plants were smaller in response to chilling and this was more pronounced in the mutant. However, both genotypes showed good vigor. F2bm3 contained a two-fold increase in the level of chlorophyll a and accumulated zeaxanthin in response to chilling compared to F2, indicating an alternative photoprotection mechanism. Unlike the wild-type F2 line, the starch content was reduced in the F2bm3 mutant and the sucrose/starch partitioning was increased in F2bm3. Few changes in the non-cellulosic cell wall sugars composition could be detected, except a higher degree of substitution of glucuronoarabinoxylan and a higher content of β-glucan in both lines in response to chilling. The lignin content in leaves did not significantly change. But the concentration of HCAs was increased in F2bm3 while it decreased in F2. Furthermore, the concentration of esterified ferulic acid (FA) was greater in F2bm3, suggesting a higher degree of cross-linking between GAX and FA under chilling treatment. Thus, the increase in arabinose substitution on the xylan backbone and the abundance of HCA in F2bm3 could increase cell wall extensibility, thereby maintaining the hydration status of the cell wall in response to chilling. In addition, the higher concentrations of HCA and chlorophyll observed in F2bm3 suggest that HCAs could function as photoprotectors, thus enhancing chilling tolerance.
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Dates et versions

hal-04454441 , version 1 (13-02-2024)

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Paternité

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  • HAL Id : hal-04454441 , version 1

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Catalina Duran Garzon, Michelle Lequart, Léo Bellenger, Alejandro Lovo, Françoise Fournet, et al.. The maize low-lignin mutant F2bm3 shows pleiotropic effects on photosynthetic and cell wall metabolisms in response to chilling. cell wall meeting, 2019, Cambridge, United Kingdom. ⟨hal-04454441⟩
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