Browsing by Author "Krens, Frans A."
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- Gene expression and physiological responses associated to stomatal functioning in Rosa×hybrida grown at high relative air humidityPublication . Carvalho, Dália R.A.; Vasconcelos, Marta W.; Lee, Sangseok; Koning-Boucoiran, Carole F.S.; Vreugdenhil, Dick; Krens, Frans A.; Heuvelink, Ep; Carvalho, Susana M. P.tHigh relative air humidity (RH ≥ 85%) during growth disturbs stomatal functioning, resulting in excessivewater loss in conditions of high evaporative demand. We investigated the expression of nine abscisic acid(ABA)-related genes (involved in ABA biosynthesis, oxidation and conjugation) and two non-ABA relatedgenes (involved in the water stress response) aiming to better understand the mechanisms underlyingcontrasting stomatal functioning in plants grown at high RH. Four rose genotypes with contrasting sen-sitivity to high RH (one sensitive, one tolerant and two intermediate) were grown at moderate (62 ± 3%)or high (89 ± 4%) RH. The sensitive genotype grown at high RH showed a significantly higher stomatalconductance (gs) and water loss in response to closing stimuli as compared to the other genotypes. More-over, high RH reduced the leaf ABA concentration and its metabolites to a greater extent in the sensitivegenotype as compared to the tolerant one. The large majority of the studied genes had a relevant role onstomatal functioning (NCED1, UGT75B2, BG2, OST1, ABF3 and Rh-APX) while two others showed a minorcontribution (CYP707A3 and BG1) and AAO3, CYP707A1 and DREB1B did not contribute to the tolerancetrait. These results show that multiple genes form a highly complex regulatory network acting togethertowards the genotypic tolerance to high RH.
- QTL analysis for stomatal functioning in tetraploid Rosa × hybrida grown at high relative air humidity and its implications on postharvest longevityPublication . Carvalho, Dália R. A.; Koning-Boucoiran, Carole F. S.; Fanourakis, Dimitrios; Vasconcelos, Marta W.; Carvalho, Susana M. P.; Heuvelink, Ep; Krens, Frans A.; Maliepaard, ChrisHigh relative air humidity (RH >= 85 %) during leaf development disturbs stomatal functioning leading to excessive water loss in conditions of high evaporative demand, resulting in severe reduction in postharvest longevity. In roses, this effect depends on the genotype, opening the possibility for breeding cultivars with more responsive stomata. In this study, we aim at identifying genomic regions associated with the control of water loss following growth at high RH. The F1 generation (108 offspring) and the two parents (P540 and P867) of a tetraploid cut rose population grown at high (85 %) RH were phenotyped for stomatal control to water loss by assessing the relative water content after 4 h of leaflet desiccation (RWC_4 h). The RWC_4 h varied between 7 and 62 % across the 110 studied individuals, with parents P540 and P867 showing 51 and 20 % RWC_4 h, respectively. Based on these data, a quantitative trait locus (QTL) analysis was performed. The impact of the identified QTLs on postharvest longevity of ten selected offspring was further evaluated. Three QTLs were identified: two major [positioned on linkage group 5 of the integrated consensus map (ICM 5) of both parents and on ICM 2 of the parent P867] and one putative minor (mapped to ICM 6 of both parents), explaining 32 % of the variability in the RWC_4 h. Low RWC_4 h was found to be a good proxy for eliminating the offspring with short vase life. This study constitutes a first step toward identifying the most likely regions for genes of interest controlling stomatal functioning in high RH-grown plants.