Overexpression of the MYB29 transcription factor affects aliphatic glucosinolate synthesis in Brassica oleracea

Isothiocyanates, the bio-active hydrolysis products of glucosinolates, naturally produced by several Brassicaceae species, play an important role in human health and agriculture. This study aims at correlating the content of aliphatic glucosinolates to the expression of genes involved in their synthesis in Brassica oleracea, and perform functional analysis of BoMYB29 gene. To this purpose, three genotypes were used: a sprouting broccoli, a cabbage, and a wild genotype (Winspit), a high glucosinolate containing accession. Winspit showed the highest transcript level of BoMYB28, BoMYB29 and BoAOP2 genes, and BoAOP2 expression was positively correlated with that of the two MYB genes. Further analyses of the aliphatic glucosinolates also showed a positive correlation between the expression of BoAOP2 and the production of sinigrin and gluconapin in Winspit. The Winspit BoMYB29 CDS was cloned and overexpressed in Winspit and in the DH AG1012 line. Overexpressing Winspit plants produced higher quantities of alkenyl glucosinolates, such as sinigrin. Conversely, the DH AG1012 transformants showed a higher production of methylsulphinylalkyl glucosinolates, including glucoraphanin, and, despite an up-regulation of the aliphatic glucosinolate genes, no increase in alkenyl glucosinolates. The latter may be explained by the absence of a functional AOP2 gene in DH AG1012. Nevertheless, an extract of DH AG1012 lines overexpressing BoMYB29 provided a chemoprotective effect on human colon cells. This work exemplifies how the genetic diversity of B. oleracea may be used by breeders to select for higher expression of transcription factors for glucosinolate biosynthesis to improve its natural, health-promoting properties

A Distinct Genetic Cluster in Cultivated Chickpea as Revealed by Genome-wide Marker Discovery and Genotyping

The accurate description of plant biodiversity is of utmost importance to efficiently address efforts in conservation genetics and breeding. Herein, we report the successful application of a genotyping-by-sequencing (GBS) approach in chickpea ( L.), resulting in the characterization of a cultivated germplasm collection with 3187 high-quality single nucleotide polymorphism (SNP) markers. Genetic structure inference, principal component analysis, and hierarchical clustering all indicated the identification of a genetic cluster corresponding to black-seeded genotypes traditionally cultivated in Southern Italy. Remarkably, this cluster was clearly distinct at both genetic and phenotypic levels from germplasm groups reflecting commercial chickpea classification into and seed types. Fixation index estimates for individual polymorphisms pointed out loci and genomic regions that might be of significance for the diversification of agronomic and commercial traits. Overall, our findings provide information on genetic relationships within cultivated chickpea and highlight a gene pool of great interest for the scientific community and chickpea breeding, which is limited by the low genetic diversity available in the primary gene pool

Genetic, bio-agronomic, and nutritional characterization of kale (Brassica oleracea L. var. acephala) diversity in Apulia, Southern Italy

Kale (Brassica oleracea L. var. acephala) is a widely appreciated vegetable with a century-old history of cultivation in Italy. The present study was addressed to the collection and characterization of kale germplasm traditionally cultivated in Apulia, Southern Italy, nowadays at risk of genetic erosion. In total, nineteen Apulian kale accessions were acquired. Genotyping by means of simple sequence repeat (SSR) DNA markers led to the identification of highly informative primer combinations and highlighted significant patterns of molecular variation among accessions. Consistently, significant differences were observed with respect to morpho-agronomic traits, including yield and harvesting time, and the content of bioactive compounds, namely total phenols, flavonoids, and anthocyanins, associated with antioxidant activity. Overall, this study led to the establishment of an ex situ collection of great importance to preserve endangered Apulian kale germplasm and to provide seed access to potential growers. Meanwhile, it offers a first characterization of Apulian kale, useful to promote its consumption and valorisation through breeding programmes