Background and Aims:  Based on parentage analysis of a large nuclear simple sequence repeat (SSR) marker database of grapevine genotypes, we propose the pedigree of several cultivars from southwestern France including Merlot, one of the world's major black winegrapes. Methods and Results:  The putative mother of Merlot, deduced from inheritance at 55 nuclear and three chloroplast microsatellite loci, is a non‐referenced and previously unknown cultivar, first sampled some years ago in northern Brittany where vines were cultivated at the end of the Middle Ages, and then identified in four places in Charentes. Considering both the name used by the growers of this grape and the literature, we have named it Magdeleine Noire des Charentes. The putative father of Merlot is Cabernet Franc, already involved in the parentage of Cabernet‐Sauvignon. Further analysis of genetic relationships leads us to propose the kinship group of Merlot composed, among others, of Carmenère (Gros Cabernet × Cabernet Franc), Merlot Blanc (Merlot × Folle Blanche), Cot (Magdeleine Noire des Charentes × Prunelard) and Mourtès (Magdeleine Noire des Charentes × Penouille). Conclusions:  These results shed new light on the origin of Merlot and on the relationships among several cultivars from southwestern France. Significance of the Study:  Our discovery of the key genetic role of a previously unknown cultivar in the origins of some significant cultivars reinforces the importance of deep exploration, before it is too late, to discover original genotypes which have not yet been collected or referenced.

Main conclusion Variations in gene expression can partially explain the difference of carotenoid accumulation in secondary phloem and xylem of fleshy carrot roots. The carrot root is well divided into two different tissues separated by vascular cambium: the secondary phloem and xylem. The equilibrium between these two tissues represents an important issue for carrot quality, but the knowledge about the respective carotenoid accumulation is sparse. The aim of this work was (i) to investigate if variation in carotenoid biosynthesis gene expression could explain differences in carotenoid content in phloem and xylem tissues and (ii) to investigate if this regulation is differentially modulated in the respective tissues by water-restricted growing conditions. In this work, five carrot genotypes contrasting by their root color were studied in control and water-restricted conditions. Carotenoid content and the relative expression of 13 genes along the carotenoid biosynthesis pathway were measured in the respective tissues. Results showed that in orange genotypes and the purple one, carotenoid content was higher in phloem compared to xylem. For the red one, no differences were observed. Moreover, in control condition, variations in gene expression explained the different carotenoid accumulations in both tissues, while in water-restricted condition, no clear association between gene expression pattern and variations in carotenoid content could be detected except in orange-rooted genotypes. This work shows that the structural aspect of carrot root is more important for carotenoid accumulation in relation with gene expression levels than the consequences of expression changes upon water restriction.

Quantitative resistance may depend on the effectiveness of PAMP-triggered immunity. This study highlights the diversity of mechanisms involved in the quantitative resistance of potato to Phytophthora infestans. The investigation focused on the implication of the hormone signalling pathways induced in four potato genotypes by a concentrated culture filtrate (CCF) of P. infestans. The genotypes were ranked according to their level of resistance to P. infestans and discriminant analysis of gene expression profiles separated the most resistant genotype from the three others, particularly because of a strong induction of the salicylic acid (SA) pathway. In this genotype, transcripts involved in the SA pathway, EDS1, WRKY1, PR-1 and PR-2, were induced by CCF. SA pathway involvement was confirmed by a peak of SA accumulation 12 h after elicitation and by the induction of jaz1 (jasmonate Zim domain protein 1) transcripts, which inhibit defence responses mediated by jasmonic acid (JA). By contrast, neither a significant induction of SA-mediated responses nor an accumulation of free SA and PR-2 were observed in the other resistant or two susceptible cultivars. Expression of genes in the ET and JA pathways was either not, or weakly, induced by CCF in potato. Finally, the involvement of signalling pathways was genotype dependent rather than correlating with resistance level.