Mechanisms of Kale (Brassica oleracea var. acephala) Tolerance to Individual and Combined Stresses of Drought and Elevated Temperature

Abstract

Rising temperatures and pronounced drought are significantly affecting biodiversity worldwide and reducing yields and quality of Brassica crops. To elucidate the mechanisms of tolerance, 33 kale accessions (B. oleracea var. acephala) were evaluated for individual (osmotic and elevated temperature stress) and combined stress (osmotic + temperature). Using root growth, biomass and proline content as reliable markers, accessions were evaluated for stress responses. Four representatives were selected for further investigation (photosynthetic performance, biochemical markers, sugar content, specialized metabolites, transcription level of transcription factors NAC, HSF, DREB and expression of heat shock proteins HSP70 and HSP90): very sensitive (392), moderately sensitive (395), tolerant (404) and most tolerant (411). Accessions more tolerant to stress conditions were characterized by higher basal content of proline, total sugars, glucosinolates and higher transcription of NAC and DREB. Under all stress conditions, 392 was characterized by a significant decrease in biomass, root growth, photosynthesis performance, fructan content, especially under osmotic and combined stress, a significant increase in HSF transcription and HSP accumulation under temperature stress and a significant decrease in NAC transcription under all stresses. The most tolerant accession under all applied stresses, 411 showed the least changes in all analyzed parameters compared with the other accessions.

Comparative Analysis of Primary Photosynthetic Reactions Assessed by OJIP Kinetics in Three Brassica Crops after Drought and Recovery

“…The previous reports on these three selected Brassica crops distinguished kale as the most drought-tolerant variety, while the Chinese cabbage was shown to be the most sensitive one, which was correlated with changes in phytohormones and their metabolic pathways [9,59]. In addition, the same Brassica crops exposed to short-term salt stress showed identical responses, with Chinese cabbage being the most sensitive and kale being the most tolerant variety [8].…”

“…A recent investigation into numerous kale accessions (Brassica oleracea var. acephala) highlighted the photosynthetic parameters PI ABS and Fv/Fm as among the most informative variables in the drought tolerance definition [59].…”

Rapid and low-cost screening for single and combined effects of drought and heat stress on the morpho-physiological traits of African eggplant (Solanum aethiopicum) germplasm

“…Single and combined heat and drought stressors adversely affect biomass production in plants such as tomatoes [ 90 ], cabbage [ 91 ], and soybeans [ 92 ]. Here, genotypes such as RV100503, RV100409, and RV100256 had the highest shoot dry weight production under heat stress conditions compared to the control, drought, and a combination of heat and drought ( S3 Table ).…”

Condições de cultivo e substratos para produção de mudas de couve-manteiga em clima Tropical

“…high phytochemical content (carotenoids, phenols, glucosinolates, and vitamins) and its high adaptability to a wide range of soil and climate conditions (Bauer et al, 2022;Díaz-Urbano et al, 2022). In northern Brazil, high rainfall and temperature throughout the year necessitate protected cultivation for collard Semina: Ciênc.…”