A manipulation of carotenoid metabolism influence biomass partitioning and fitness in tomato

Abstract Main conclusion The molecular mechanism underlying white petal color in Brassica napus was revealed by transcriptomic and metabolomic analyses. Abstract Rapeseed (Brassica napus L.) is one of the most important oilseed crops worldwide, but the mechanisms underlying flower color in this crop are known less. Here, we performed metabolomic and transcriptomic analyses of the yellow-flowered rapeseed cultivar ‘Zhongshuang 11’ (ZS11) and the white-flowered inbred line ‘White Petal’ (WP). The total carotenoid contents were 1.778-fold and 1.969-fold higher in ZS11 vs. WP petals at stages S2 and S4, respectively. Our findings suggest that white petal color in WP flowers is primarily due to decreased lutein and zeaxanthin contents. Transcriptome analysis revealed 10,116 differentially expressed genes with a fourfold or greater change in expression (P-value less than 0.001) in WP vs. ZS11 petals, including 1,209 genes that were differentially expressed at four different stages and 20 genes in the carotenoid metabolism pathway. BnNCED4b, encoding a protein involved in carotenoid degradation, was expressed at abnormally high levels in WP petals, suggesting it might play a key role in white petal formation. The results of qRT-PCR were consistent with the transcriptome data. The results of this study provide important insights into the molecular mechanisms of the carotenoid metabolic pathway in rapeseed petals, and the candidate genes identified in this study provide a resource for the creation of new B. napus germplasms with different petal colors.

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Potassium Application Positively Modulates Physiological Responses of Cocoa Seedlings to Drought Stress

Agronomy ◽

10.3390/agronomy11030563 ◽

2021 ◽

Vol 11 (3) ◽

pp. 563

Author(s):

Esther Anokye ◽

Samuel T. Lowor ◽

Jerome A. Dogbatse ◽

Francis K. Padi

Keyword(s):

Water Stress ◽

Soil Water ◽

Chlorophyll Content ◽

Electrolyte Leakage ◽

Seedling Survival ◽

Biomass Accumulation ◽

Biomass Partitioning ◽

Chlorophyll Content And Fluorescence ◽

Physiological Functions ◽

Soil Water Stress

With increasing frequency and intensity of dry spells in the cocoa production zones of West Africa, strategies for mitigating impact of water stress on cocoa seedling survival are urgently required. We investigated the effects of applied potassium on biomass accumulation, physiological processes and survival of cocoa varieties subjected to water stress in pot experiments in a gauzehouse facility. Four levels of potassium (0, 1, 2, or 3 g/plant as muriate of potash) were used. Soil water stress reduced plant biomass accumulation (shoot and roots), relative water content (RWC), chlorophyll content and fluorescence. Leaf phenol and proline contents were increased under water stress. Additionally, compared to the well-watered conditions, soils under water stress treatments had higher contents of exchangeable potassium and available phosphorus at the end of the experimental period. Potassium applied under well-watered conditions reduced leaf chlorophyll content and fluorescence and increased leaf electrolyte leakage, but improved the growth and integrity of physiological functions under soil water stress. Potassium addition increased biomass partitioning to roots, improved RWC and leaf membrane stability, and significantly improved cocoa seedling survival under water stress. Under water stress, the variety with the highest seedling mortality accumulated the highest contents of phenol and proline. A significant effect of variety on plant physiological functions was observed. Generally, varieties with PA 7 parentage had higher biomass partitioning to roots and better seedling survival under soil moisture stress. Proportion of biomass partitioned to roots, RWC, chlorophyll fluorescence and leaf electrolyte leakage appear to be the most reliable indicators of cocoa seedling tolerance to drought.

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