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bioRxiv · 10.1101/2023.11.14.566984

A tomato ethylene-insensitive mutant displays altered growth and higher β-carotene levels in fruit

Gupta, S. K.·Santisree, P.·Gupta, P.·Kilambi, H. V.·Sreelakshmi, Y.·Sharma, R.
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Abstract

The mutants insensitive to ethylene are helpful in deciphering the role of ethylene in plant development. We isolated an ethylene-insensitive tomato (Solanum lycopersicum) mutant by screening for acetylene-resistant (atr-1) seedlings. The atr-1 mutant displayed resistance to kinetin, suggesting attenuation of the ethylene sensing response. atr-1 also exhibited resistance to ABA- and glucose-mediated inhibition of seed germination. Unlike the Never- ripe (Nr) mutant, atr-1 seedlings were resistant to glucose, indicating ethylene sensing in atr-1 is located in a component distinct from Nr. Metabolically, atr-1 seedlings had lower levels of amino acids but higher levels of several phytohormones, including ABA. atr-1 plants grew faster and produced more flowers, leading to a higher fruit set. However, the atr- 1 fruits took a longer duration to reach the red-ripe (RR) stage. The ripened atr-1 fruits had higher {beta}-carotene levels, retained high {beta}-carotene and lycopene levels post-RR stage. The metabolome profiles of post-RR stage atr-1 fruits revealed increased levels of sugars. The atr-1 had a P279L mutation in the GAF domain of the ETR4, a key ethylene receptor regulating tomato ripening. Our study highlights that novel alleles in ethylene receptors may aid in enhancing the nutritional quality of tomato.

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Gupta, S. K., Santisree, P., Gupta, P., Kilambi, H. V., Sreelakshmi, Y., Sharma, R.. 2023-11-14. A tomato ethylene-insensitive mutant displays altered growth and higher β-carotene levels in fruit. https://doi.org/10.1101/2023.11.14.566984

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