Phytohormone signalling pathways have an important role in defence against pathogens mediated by cell-surface pattern recognition receptors and intracellular nucleotide-binding leucine-rich repeat ...class immune receptors
(NLR). Pathogens have evolved counter-defence strategies to manipulate phytohormone signalling pathways to dampen immunity and promote virulence
. However, little is known about the surveillance of pathogen interference of phytohormone signalling by the plant innate immune system. The pepper (Capsicum chinense) NLR Tsw, which recognizes the effector nonstructural protein NSs encoded by tomato spotted wilt orthotospovirus (TSWV), contains an unusually large leucine-rich repeat (LRR) domain. Structural modelling predicts similarity between the LRR domain of Tsw and those of the jasmonic acid receptor COI1, the auxin receptor TIR1 and the strigolactone receptor partner MAX2. This suggested that NSs could directly target hormone receptor signalling to promote infection, and that Tsw has evolved a LRR resembling those of phytohormone receptors LRR to induce immunity. Here we show that NSs associates with COI1, TIR1 and MAX2 through a common repressor-TCP21-which interacts directly with these phytohormone receptors. NSs enhances the interaction of COI1, TIR1 or MAX2 with TCP21 and blocks the degradation of corresponding transcriptional repressors to disable phytohormone-mediated host immunity to the virus. Tsw also interacts directly with TCP21 and this interaction is enhanced by viral NSs. Downregulation of TCP21 compromised Tsw-mediated defence against TSWV. Together, our findings reveal that a pathogen effector targets TCP21 to inhibit phytohormone receptor function, promoting virulence, and a plant NLR protein has evolved to recognize this interference as a counter-virulence strategy, thereby activating immunity.
Plants have evolved hundreds of nucleotide-binding and leucine-rich domain proteins (NLRs) as potential intracellular immune receptors, but the evolutionary mechanism leading to the ability to ...recognize specific pathogen effectors is elusive.
Here, we cloned Pvr4 (a Potyvirus resistance gene in Capsicum annuum) and Tsw (a Tomato spotted wilt virus resistance gene in Capsicum chinense) via a genome-based approach using independent segregating populations.
The genes both encode typical NLRs and are located at the same locus on pepper chromosome 10. Despite the fact that these two genes recognize completely different viral effectors, the genomic structures and coding sequences of the two genes are strikingly similar. Phylogenetic studies revealed that these two immune receptors diverged from a progenitor gene of a common ancestor.
Our results suggest that sequence variations caused by gene duplication and neofunctionalization may underlie the evolution of the ability to specifically recognize different effectors. These findings thereby provide insight into the divergent evolution of plant immune receptors.
Capsaicinoids are pungent compounds used for industrial and medical purposes including food, medicine and cosmetics. The Indian local variety ‘Bhut Jolokia’ (Capsicum chinense Jacq.) is one of the ...world's hottest chilli peppers. It produces more than one million Scoville heat units (SHUs) in total capsaicinoids. In this study, our goal was to identify quantitative trait loci (QTLs) responsible for the high content of capsaicin and dihydrocapsaicin in ‘Bhut Jolokia’. Capsicum annuum ‘NB1’, a Korean pepper inbred line containing 14 000 SHUs, was used as a maternal line. An F2 population derived by crossing between ‘NB1’ and ‘Bhut Jolokia’ was generated to map QTLs for capsaicinoids content. A total of 234 markers, including 201 HRM, 21 SSR, 2 CAPS and 10 gene‐based markers of the capsaicinoid synthesis pathway, were mapped. The final map covered a total distance of 1175.2 cM and contained 12 linkage groups corresponding to the basic chromosome number of chilli pepper. Capsaicin and dihydrocapsaicin content were analysed in 175 F2 pepper fruits using the HPLC method. The maximum total capsaicinoids content was 1389 mg per 100g DW (dry weight), and the minimum content was 11 mg per 100g DW. Two QTLs (qcap3.1 and qcap6.1) for capsaicin content were identified on LG3 and LG6, and two QTLs (qhdc2.1 and qdhc2.2) for dihydrocapsaicin content were located on LG2. We did not detect QTLs for total capsaicinoids content. The QTL positions for capsaicin content were different from those for dihydrocapsaicin content. These results indicate that the complexity of selecting for more pungent chilli peppers must be considered in a chilli pepper breeding programme. The QTL‐linked markers identified here will be helpful to develop more pungent pepper varieties from ‘Bhut Jolokia’, a very hot pepper.
•The consumptive use (CU) and stage-specific crop coefficient (Kc) for was measured.•The Kc values determined over the growing period was slightly different from that suggested by FAO 56 for ...pepper.•The crop factor increased from crop germination to its peak during the mid stage, but decreased during crop senescence.•The regionally based growth-stage-specific Kc is helpful in irrigation scheduling and management.
This research was conducted to determine growth stage-specific crop coefficient (Kc) and Consumptive Use (CU), for Capsicum chinense (Ata rodo) grown under irrigation in Omu-Aran, North central Nigeria. Daily CU and growth stage-specific crop coefficient Kc for Capsicum chinense was measured using a developed and calibrated hydraulic weighing lysimeter over 2 consecutive dry seasons (2015/16 and 2016/17). The values of CU and growth stage-specific Kc obtained were compared to that estimated using CROPWAT 8.0 and with existing Food and Agricultural Organization (FAO) Kc values for bell pepper. The Kc values determined over the growing seasons varied from 0.32 to 0.7, 1.02 to 1.45 and 0.76 to 0.9 representing Kc initial, Kc mid-season and Kc late season (Kcini, Kcmid and Kcend), respectively. These Kc varied significantly (P < 0.05) from FAO established Kc values. The observed Kc was validated using relevant statistical methods. The seasonal CU of Capsicum chinense was 580.01 ± 54 mm, while the reference evapotranspiration increased from 3.26 mm day−1 in October to 4.19 mm day−1 in February. The crop factor increased from 0.7 in October to attain its peak of 1.45 in January, but decreased to 0.9 during crop senescence in February. Likewise, the daily crop water need was 2.28 mm day−1 in October but reached its peak of 5.82 mm day−1 in January and thereafter decreased to 3.77 mm day−1 in February. Mean monthly water need of Capsicum chinense pepper was 68.36 mm month−1 in October. The water need of crop rose to its peak of 166.32 mm month−1 in December, and thereafter declined to 113.13 mm month−1 in February It is inferred that the application of growth stage-specific Kc will assist in irrigation management and would serve as useful guide for precise water applications for areas around Omu-Aran as it differs from region to region.
•Capsaicinoid production of hot pepper cultivars showed different responses to water stresses.•Capsaicinoid accumulation of hot pepper cultivars with larger fruit and higher pungency was more ...increased by water stress.•Optimum water stress could increase capsaicinoid yield in some but not all C. chinense hot pepper cultivars.•Mild water stress increased capsaicinoid yield of hot pepper F1-hybrid, Akanee Pirote.
Although water stress reduces fruit yield, it also increases capsaicinoid accumulation in hot pepper. The aim of this study was to investigate the effect of different water regimes on capsaicinoid production in Capsicum chinense Jacq. having different pungency levels. Four hot pepper (C. chinense) cultivars were planted with four water regimes after anthesis: daily irrigation (control; S1), every 2 days (S2), every 3 days (S3) and every 4 days (S4). The results found that Akanee Pirote with the S2 treatment gave the highest capsaicinoid yield, and the increase of capsaicinoid yield was attributed from increasing the absolute capsaicinoid content and reducing the dry fruit yield as compared to the control. Capsaicinoid yield of Bhut Jolokia, Orange Habanero, and BGH1719 responded to the water stresses, but produced less capsaicinoid yield as compared to the control. This study reveals that appropriate water stress could increase capsaicinoid yield in some, but not all, hot pepper cultivars.
Se realizo la cinética de secado de tres variedades de ají, Habanero (Capsicum chinense), Jalapeño (Capsicum annum) y Amarillo (Capsicum baccatum), donde se logró obtener experimentalmente la ...cinética del secado, fue realizado utilizándose un secador laboratorial de bandejas, a temperatura constante de 70 °C. El tiempo requerido para secar el producto hasta una humedad aproximada del 34 % fue de 10 horas. Las curvas experimentales del secado fueron ajustados al modelo difusional de Lewis, Pague y Henderson & Pabis. Se determina que la velocidad de secado a una temperatura constante favorece a la transferencia de masa y energía. En la que estableció que el modelo que tuvo mayor ajuste tanto para la cinética de secado y deshidratación fue de Henderson & Pabis dando como resultado R2 = 73,130 % para el secado y R2 = 71,631 para la deshidratación, obteniendo al final un producto con una humedad relativamente nula y de fácil trituración, logrando obtener un polvo homogéneo y conservando sus características multifuncionales tanto en su uso gastronómico como también en el uso de prevención de enfermedades.
Palabras Claves: Capsicum annum; Capsicum chinense; Capsicum baccatum; Cinética; Deshidratación; Velocidad de flujo; Temperatura; Humedad.
ABSTRACT Cultivation and commercialization of Capsicum pepper have great importance in Brazil. This work assessed the influence of omission of macro and micronutrients on the growth and mineral ...nutrition of sweet pepper plants (Capsicum chinense Jacquin). The research was carried out in a greenhouse with washed sand as substrate. The experimental design was completely randomized with five replications and eight treatments: complete (control), omission of N, P, K, Ca, Mg, S, and micronutrients (B, Cu, Fe, Mn and Zn). The plants were submitted to the treatments when they reached an average height of 20 cm and the nutrient solution was supplied by percolation in plastic pots and renewed every 15 days. Nutrients omission affected negatively plant growth as a whole. The omission of N, Ca, and micronutrients greatly reduced sweet pepper yield. The C. chinense plants presented the sequence by dry matter production of shoots and roots in descending order: COMP > OP > OS > OK > Omg > ON > Oca > OMicro.
【Objective】Capsicum chinense is one of the main cultivated species of pepper, which generally has a strong fruit aroma formed by branched chain esters. AAT (alcohol acyl-CoA transferase) catalyzes ...the last step in the synthesis of branched chain esters and has an important impact on its content. Identification of the AAT gene family in C. chinense and analysis on its expression patterns will provide references for its functional studies.【Method】Bioinformatics and real-time quantitative PCR analysis were applied to identify the AAT gene family of C. chinense and analyze its expression patterns.【Result】Ten members of the AAT gene family were identified and named CcAAT1-CcAAT10 according to their distribution order on six chromosomes. Physicochemical properties prediction revealed that the length of amino acid sequence encoded by AAT gene family range from 256 to 683 aa, with their molecular mass ranging from 29 to 77 kDa, and isoelectric point ranging from 5.34 to 8.79. Average hydrophobic coefficients of them were all negative values. Their instability indexes ranged 23.76 to 51.02. Protein structure prediction showed that their secondary structure was dominated by α-helices and irregular convolutions, and the tertiary structure varied widely. Subcellular localization prediction revealed that all CcAAT were located in the cytoplasm and 16 cis-regulatory elements were found on their gene promoter. Spatiotemporal expression analysis showed that CcAAT5 and CcAAT6 had no detectable expression, CcAAT8 was specifically expressed in flowers and fruits, CcAAT1, CcAAT3 and CcAAT7 were highly expressed in leaves, and CcAAT4 was highly expressed in roots.【Conclusion】It clarified the expression pattern of the AAT gene family in C. chinense and it was hypothesized that CcAAT8 might be a key gene affecting the content of branched chain esters.
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