Genetic resources of chili pepper (Capsicum annuum L.) against Phytophthora capsici and their induction through various biotic and abiotic factors

Elucidation of the biochemical and molecular basis of the differential disease expression in two cultivars of chili (Capsicum annuum) in response to Colletotrichum capsici infection

Chili plants are affected by the hemibiotrophic ascomycota fungus Colletotrichum capsici causing Anthracnose. Infection results in yield and marketability loss due to a decrease in the quality of fruits. The study of morphological symptom development in two cultivars, Bullet, and Beldanga, showed very different disease expression pattern. To understand the reasons behind such differential response, we investigated, in a time-dependent manner, biochemical activities of important defense enzymes, PR proteins, like peroxidase, polyphenol-oxidase, phenylalanine ammonia lyase, β-glucanase, chitinase, catalase, as well as phenols, flavonoids, chlorophyll and the key signaling molecule nitric oxide in their leaves. We further performed real-time nitric oxide (NO) detection studies. The results showed striking differences in the activity profile of these defense molecules through the course of the study. We monitored the gene expression levels of 12 important defense-related genes under in vivo condition. The transcription levels were mostly increased in the tolerant cultivar till 7 days post-infection (DPI), while downregulation of some of the genes were observed in the susceptible one. These data indicated that disease manifestation is a simulated response of these defense molecules which can nullify the effect of the pathogen and its products, when resistance occurs. Alternatively, the pathogen suppresses the host defense when the disease develops.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11738-021-03334-x.

An integrative Study Showing the Adaptation to Sub-Optimal Growth Conditions of Natural Populations of Arabidopsis thaliana: A Focus on Cell Wall Changes

In the global warming context, plant adaptation occurs, but the underlying molecular mechanisms are poorly described. Studying natural variation of the model plant Arabidopsisthaliana adapted to various environments along an altitudinal gradient should contribute to the identification of new traits related to adaptation to contrasted growth conditions. The study was focused on the cell wall (CW) which plays major roles in the response to environmental changes. Rosettes and floral stems of four newly-described populations collected at different altitudinal levels in the Pyrenees Mountains were studied in laboratory conditions at two growth temperatures (22 vs. 15 °C) and compared to the well-described Col ecotype. Multi-omic analyses combining phenomics, metabolomics, CW proteomics, and transcriptomics were carried out to perform an integrative study to understand the mechanisms of plant adaptation to contrasted growth temperature. Different developmental responses of rosettes and floral stems were observed, especially at the CW level. In addition, specific population responses are shown in relation with their environment and their genetics. Candidate genes or proteins playing roles in the CW dynamics were identified and will deserve functional validation. Using a powerful framework of data integration has led to conclusions that could not have been reached using standard statistical approaches.

Implement of Biotic and Abiotic Stress for Enhancement and Production of Capsaicin in Suspension Cultures of <I>Capsicum annum</I> spp

BACKGROUND AND OBJECTIVE

Pepper (Capsicum annuum L.) is one of the major vegetable and spice crops grown worldwide. This study highlighted the economic and importance process for in vitro capsaicin production from pepper plant. As well as to study the effect of MS medium supplemented with 2,4-D in combinations with 0.2 mg L-1 Kin. for callus and suspension production was implemented. As well as, the influence of A. niger as biotic and methyl jasmonate as abiotic elicitors on capsaicin accumulation was investigated.

MATERIALS AND METHODS

For this purpose, callus cultures were prepared from seeds of pepper and subcultured. After 28 days, calli formation (%), fresh weight (g/Jar) and dry weight (g/Jar) was calculated. Cell number and packed cell volume were calculated from their cell suspension. In the end, capsaicin was extracted and colorimetrically quantified.

RESULTS

The highest percentage of calli formation was recorded with hypocotyl, leaf and root explants, respectively. The MS medium fortified with 3.0 mg L-1 2,4-D+0.2 mg L-1 Kin. In addition, the maximum P.C.V was recorded after 16 days of cultivation on the same medium. Furthermore, it was found that fortified MS medium with 1.5% of A. niger in combination with 100 μM of methyl jasmonate achieved of cell growth parameters and capsaicin accumulation in significant rate during 16 days of cultivation.

CONCLUSION

Fortified of MS medium with 3.0 mg L-1 2,4-D+0.2 mg L-1 Kin. showed the optimized medium for both callus and suspension production. Moreover, augmentation of MS medium with 1.5% of A. niger in combination with 100 μM of methyl jasmonate enhanced of capsaicin accumulation in significant rate during 16 days of cultivation.