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Key message: Through comprehensive genomic and transcriptomic analyses, we identified a set of 23 genes that act up- or downstream of erucic acid content (EAC) production in rapeseed seeds. We selected example genes to showcase the distribution of single nucleotide polymorphisms, haplotypes associated with EAC phenotypes, and the creation of molecular markers differentiating low EAC and high EAC genotypes. Erucic acid content (EAC) is a crucial trait in rapeseed, with low LEAC oil recognized for its health benefits and high EA oil holding industrial value. Despite its significance, the genomic consequences of intensive LEAC-cultivar selection and the genetic basis underlying EA regulation remain largely unexplored. To address this knowledge gap, we conducted selective signal analyses, genome-wide association studies (GWAS), and transcriptome analyses. Our investigation unveiled the genetic footprints resulting from LEAC selection in germplasm populations, drawing attention to specific loci that contribute to enriching diversity. By integrating GWAS and transcriptome analyses, we identified a set of 23 genes that play a significant role in determining EAC in seeds or are downstream consequences of EA-level alterations. These genes have emerged as promising candidates for elucidating the potential mechanisms governing EAC in rapeseed. To exemplify the findings, we selected specific genes to demonstrate the distribution of single nucleotide polymorphisms and haplotypes associated with different EAC phenotypes. Additionally, we showcased to develop molecular markers distinguishing between LEAC and high EAC genotypes. [ABSTRACT FROM AUTHOR]

Arabidopsis seeds accumulate considerable fatty acids (FA/s) from embryo until maturity. The environmental stimuli and the regulatory factors that determine FA accumulation, however, remain unclear. In this study, we investigated the role of DELLAs, the negative regulatory factors in the gibberellin transduction pathway, in seed oil formation in Arabidopsis. Seed morphology, weight-per-thousand seeds, oil content, and FA composition were compared among the seeds of the DELLA ga1- 3 rga- t2 rgl2- 1 ( triple), ga1- 3 rga- t2 rgl1- 1rgl2- 1 ( quadruple), ga1- 3 gai- t6 rga- t2 rgl1- 1 rgl 2- 1 ( penta), and wild type (WT), Landsberg erecta (L er). Significant differences between the WT and the penta mutant for the above traits were observed. Compared with WT, the penta seeds were characterized by a decrease of 22 % seed oil in term of μg/mg, an increment of 10 % seed oil in term of FA/seed, and an alteration of FA composition. In general, the dynamics of FA accumulation in the penta and WT developing seeds (2-16 days after anthesis, DAA) were not obviously different. However, there was higher FA accumulation in penta seeds from 6 DAA compared with WT. RNA gel blotting indicated that the fatty acid desaturase genes were expressed in seeds as well as in leaves. The different transcript levels of the genes between the penta mutant and WT unveiled a part of the reasons accounting for the differences observed. To our knowledge, this is the first report on the effect of DELLAs on the dynamic process of seed oil formation of a flowering plant. [ABSTRACT FROM AUTHOR]

Colored cotton is a very attractive proposition for the textile industry as it reduces the cost for dying. However, inferior fiber quality and non uniform color make it unsuitable for heavy machine spinning. Due to this reason cultivation of colored cotton on commercial scale has been restricted by cotton growers. The current study was planned to unveil the process of fiber development in isogenic lines of brown, green and white cotton by comparing their fiber length, flavonoid, cellulose, carbohydrate and enzyme activities (SuSy, SPS, acid invertase, Cox, NAD+, NADH, NADP+, and NADPH). White cotton fiber exhibited high cellulose contents (915.81 mg g) and long fibers (3.07 cm) as compared to colored cotton fibers with low cellulose content (787.63 and 780.66 mg g) and shorter fiber length (2.54 and 2.48 cm). Similarly the amount of flavonoids also varied significantly with maximum concentration (8.67 and 7.13 mg g) in brown and green cotton fiber at 5 DPA as compared to white cotton fiber (3.12 mg g) at 0 DPA. This high concentration of flavonoid not only lowered the total amount of carbohydrates but also lowered the sucrose transformation rate to developing cotton fiber in colored cotton. The activity of different enzymes (AI, SuSy and SPS, Cox, NAD+/NADH and coenzymes NADP+/NADPH involved in the metabolism of carbohydrates was higher in brown cotton fiber than green cotton fiber. However, high activity of these enzymes did not always correlated with higher amount of cellulose thus indicated the involvement of complex mechanisms for cellulose and flavonoid synthesis during the development of cotton fiber. [ABSTRACT FROM AUTHOR]

In order to study the effect of phytohormones on cotton fiber initiation, contents of four endogenous phytohormones and activities of four related enzymes in ovules (in vivo) of a fuzzless–lintless mutant (fl) and its wild-type (FL) line were measured from 4 days before anthesis (day −4) to 4 days after anthesis (day 4). The results showed that contents of indole-3-acetic acid, gibberellic acid (GA), and zeatin riboside in fl ovules were lower than those in FL ovules. Therefore, indole-3-acetic acid, GA, and zeatin riboside were thought to be the promoters of fiber initiation. Although abscisic acid (ABA) content in fl ovule was slightly higher than that in FL ovule on day 0, which might imply that ABA inhibited fiber initiation. Fiber initiation could also be influenced by enzyme through regulating synthesis and degradation of related phytohormones since fl ovules were significantly higher in activities of indole-3-acetic acid oxidase, cytokinin oxidase and peroxidase, but lower in activity of tryptophan synthetase than those in FL ovules. To test the above hypothesis, exogenous plant growth regulators were also applied for the culture of ovules from fl and FL in vitro. When no regulators were added, no fiber was induced on fl ovule, but a few fibers were induced in FL ovule. Higher total fiber units (TFU) were observed when indole-3-acetic acid and gibberellic acid (GA3) were applied either separately or in combination to media. TFU did not increased with zeatin riboside alone, but the highest TFU was achieved when zeatin riboside was applied together with indole-3 acetic acid and GA3, which implied that fiber initiation could be promoted by them as additive. [ABSTRACT FROM AUTHOR]