Effet De La Fertilisation Phospho-Potassique Sur Le Rendement Grainier Et La Qualite Des Semences De Cajanus Cajan L. Millsp. Sur Un Ferrasol A Yamoussoukro, Region Centre De La Cote D’ivoire

The aim of the present work was to evaluate the effect of phosphorus and potassium fertilization on the production and the quality of pigeon pea seeds produced on a ferrasol type sol. A completely randomized block design was used, in a 2x3x3 factorial set with three replications. A density of 20 000 plants ha -1 was used. The treatments were 0, 40, 80, units for phosphorus (P2O5) and potassium (KCl). Treatment which received P80K80 fertilization had greater productivity (650 kg) but a low germination rate (30 %). The optimal dose (523 kg and 90 % germination rate) was obtained with P40K80, followed by P40K40 dose (516 kg and 82 % germination rate). Phosphorus and potassium had mutually acted and influenced positively the production and the quality of the seeds of C. cajan

Breeding for carrot resistance to Alternaria dauci without compromising taste

Developing carrot varieties highly resistant to Alternaria dauci is a top priority for breeders. Meanwhile, consumers are increasingly demanding as regards final product quality, particularly taste. Bitterness is one of the five common taste sensations, but it is rejected by most carrot consumers. Therefore, providing tools for efficient plant breeding of resistant, low bitter carrots would be helpful. While resistance QTLs (rQTLs) have already been identified for carrot resistance to A. dauci, the genetic control and mapping of the metabolites involved in bitterness perception have not been addressed so far. We identified the metabolites most involved in bitterness by combining chemical and sensory analyses of a set of resistant and susceptible carrot genotypes grown in different environments. We evaluated their genetic control and heritability in a segregating F2:3 population over 2 years of field trials and searched for colocalizations between rQTLs and metabolite QTLs (mQTLs) to evaluate the link between bitterness and resistance traits. Our results suggest that it is possible to increase resistance while favoring low bitter varieties by selecting genomic regions involved in the expression of one or the other trait and counter-selecting others when r- and mQTL colocalization is unfavorable

Resistant carrots to Alternaria dauci or tasty carrots: should we choose?

International audienceThe carrot ideotype for carrot breeders could be a variety resistant to Alternaria leaf blight-the main foliar disease on carrot worldwide-with a low level of bitterness as consumers consider it as an undesirable taste of carrots. Our previous investigation on carrot resistance to Alternaria dauci allowed the identification of resistance QTLs (rQTLs). Based on these results, breeding for a higher level of resistance is possible but we could interrogate about the impact of selecting these genomic regions on carrot bitterness. To answer this question, we combined chemical and sensorial analyses of a set of resistant and susceptible carrot genotypes evaluated in different environments to identify the metabolites involved in bitterness. The genetic control and heritability field experimentation and colocalizations between rQTLs and metabolite QTLs (mQTLs) were searched in order to evaluate the link between bitterness and resistance traits. Our results showed that selecting the genomic regions mainly involved in carrot resistance is possible without compromising carrot taste. However, the colocalization of rQTLs and mQTLs suggest that some genomic regions are involved in the expression of both traits and should be avoided or even counter selected. INTRODUCTION While breeding for varieties highly resistant to Alternaria dauci is a top priority for carrot seed companies, consumers are more and more demanding on gustative quality, especially low bitter carrots. Amon others, terpens and polyacetylenes are considered key compounds for bitterness in carrots (Simon et al. 1980; Seljasen et al. 2001). Relying on sensory and chemical analyses, Kreutzmann et al. (2008) highlighted that a small number of metabolites, among them eight terpens, could predict bitterness. However, while the genetic control of carrot resistance to A. dauci has already been investigated, leading to the identification of rQTLs (Quantitative Trait Loci involved in resistance) in different genetic backgrounds (Le Clerc et al., 2009; 2015), no information were available except very recently published by Keilwagen at al. (2017) on terpens and polyacetylenes. Identifying the genomic regions involved in resistance and/or bitterness will be very helpful for breeders to develop resistant varieties while avoiding increasing bitterness. To answer this question, chemical and sensory analyses were performed on a set of five carrot genotypes during three years, in four environments to identify the terpens involved in bitterness. These metabolites were characterized during two consecutive years in field trials in a population already segregating for resistance to Alternaria dauci and their genetic control was determined. The colocalization between previously identified rQTLS and mQTLS (QTLs involved in the accumulation of metabolites) were examined and recommendations were made for breeders

Novel Dormancy Mechanism of Castration Resistance in Bone Metastatic Prostate Cancer Organoids

Advanced prostate cancer (PCa) patients with bone metastases are treated with androgen pathway directed therapy (APDT). However, this treatment invariably fails and the cancer becomes castration resistant. To elucidate resistance mechanisms and to provide a more predictive pre-clinical research platform reflecting tumor heterogeneity, we established organoids from a patient-derived xenograft (PDX) model of bone metastatic prostate cancer, PCSD1. APDT-resistant PDX-derived organoids (PDOs) emerged when cultured without androgen or with the anti-androgen, enzalutamide. Transcriptomics revealed up-regulation of neurogenic and steroidogenic genes and down-regulation of DNA repair, cell cycle, circadian pathways and the severe acute respiratory syndrome (SARS)-CoV-2 host viral entry factors, ACE2 and TMPRSS2. Time course analysis of the cell cycle in live cells revealed that enzalutamide induced a gradual transition into a reversible dormant state as shown here for the first time at the single cell level in the context of multi-cellular, 3D living organoids using the Fucci2BL fluorescent live cell cycle tracker system. We show here a new mechanism of castration resistance in which enzalutamide induced dormancy and novel basal-luminal-like cells in bone metastatic prostate cancer organoids. These PDX organoids can be used to develop therapies targeting dormant APDT-resistant cells and host factors required for SARS-CoV-2 viral entry