Plant coloration,a key trait for attracting pollinators and seed dispersers,is dynamically adjustable in response to temperature.However,the molecular mechanisms underlying temperature-dependent peel pigmentation in c...Plant coloration,a key trait for attracting pollinators and seed dispersers,is dynamically adjustable in response to temperature.However,the molecular mechanisms underlying temperature-dependent peel pigmentation in citrus remain poorly understood.In this study,through a multi-site geographical analysis of Newhall navel oranges across 32 locations in China,we revealed a distinct latitudinal distribution of oranges,with redder peel coloration at higher latitudes.Subsequent correlation analysis and postharvest treatments pinpointed the suboptimal low temperature range of 10℃-16℃ as the primary determinant for the peel pigmentation.Combined transcriptomic and functional analyses identified CsHB7 as an essential early regulator mediating low-temperature-induced peel pigmentation.Further investigation unveiled a CsWRKY3-CsHB7 transcriptional cascade that directly responds to low temperature and promotes peel pigmentation by activating the expression of CsCCD4b,which encodes a key enzyme for the synthesis of the red pigmentβ-citraurin.Moreover,we demonstrated that the CsWRKY3-CsHB7 module,mediated by the W-box cis-element in the CsHB7 promoter,contributes to natural variation in suboptimal low-temperature-induced pigmentation.Our findings decrypt a key regulatory mechanism of citrus peel pigmentation,reveal a genetic basis for further evolutionary studies,and provide molecular tools for climate-resilient citrus breeding.展开更多
基金supported by the National Key R&D Program of China(2022YFF1003100)the Foundation of Hubei Hongshan Laboratory(2021hszd009)+2 种基金the National Modern Agricultural(Citrus)Technology Systems of China(no.CARS-26)the Fundamental Research Funds for the Central Universities(no.2662022YLYJ001)the Special Projects for Central Government-Guided Local Science and Technology Development in Hubei Province(no.2024EIA029).
文摘Plant coloration,a key trait for attracting pollinators and seed dispersers,is dynamically adjustable in response to temperature.However,the molecular mechanisms underlying temperature-dependent peel pigmentation in citrus remain poorly understood.In this study,through a multi-site geographical analysis of Newhall navel oranges across 32 locations in China,we revealed a distinct latitudinal distribution of oranges,with redder peel coloration at higher latitudes.Subsequent correlation analysis and postharvest treatments pinpointed the suboptimal low temperature range of 10℃-16℃ as the primary determinant for the peel pigmentation.Combined transcriptomic and functional analyses identified CsHB7 as an essential early regulator mediating low-temperature-induced peel pigmentation.Further investigation unveiled a CsWRKY3-CsHB7 transcriptional cascade that directly responds to low temperature and promotes peel pigmentation by activating the expression of CsCCD4b,which encodes a key enzyme for the synthesis of the red pigmentβ-citraurin.Moreover,we demonstrated that the CsWRKY3-CsHB7 module,mediated by the W-box cis-element in the CsHB7 promoter,contributes to natural variation in suboptimal low-temperature-induced pigmentation.Our findings decrypt a key regulatory mechanism of citrus peel pigmentation,reveal a genetic basis for further evolutionary studies,and provide molecular tools for climate-resilient citrus breeding.
