New insights in plant immunity and protection of Papaver somniferum against pathogens

Ing. Jhonny Stalyn HERNANDEZ OROZCO

Disertační práce

Abstract:

This PhD thesis integrates fundamental research on plant defence signalling (plant immunity) with the development of innovative, sustainable crop protection strategies. We initially utilized the model plant Arabidopsis thaliana to demonstrate that high endogenous salicylic acid (SA) levels negatively regulate anthocyanin accumulation under abiotic stress. We established, also within the frame of the thesis, oilseed poppy (Papaver somniferum), an economically important crop in the Czech Republic, as our model crop plant. We provided the first comprehensive methodological pipeline for analysing pattern-triggered immunity (PTI) in poppy. We monitored in detail the poppy response to flg22, which moderately induced conserved immune reactions across blue and white seed cultivars. I optimized protocols for oilseed poppy callus induction and regeneration across broad oilseed poppy cultivars, and established a necessary technical basis for future opium/oilseed poppy transformation and gene-editing applications. To address the threat of fungal pathogens Alternaria papavericola and Sclerotinia sclerotiorum, I established particular pathosystems. I have validated that spray-induced gene silencing (SIGS) is a viable, non-GMO disease control strategy for A. papavericola and S. sclerotiorum on oilseed poppy plants. I successfully demonstrated that exogenous application of doublestranded RNA (dsRNA) targeting essential pathogenicity genes significantly reduced infection severity and lesion development. In summary, these findings advance the mechanistic understanding of poppy innate immunity and provide practical biotechnological tools for enhancing disease resistance in modern agriculture.

Abstract:

This PhD thesis integrates fundamental research on plant defence signalling (plant immunity) with the development of innovative, sustainable crop protection strategies. We initially utilized the model plant Arabidopsis thaliana to demonstrate that high endogenous salicylic acid (SA) levels negatively regulate anthocyanin accumulation under abiotic stress. We established, also within the frame of the thesis, oilseed poppy (Papaver somniferum), an economically important crop in the Czech Republic, as our model crop plant. We provided the first comprehensive methodological pipeline for analysing pattern-triggered immunity (PTI) in poppy. We monitored in detail the poppy response to flg22, which moderately induced conserved immune reactions across blue and white seed cultivars. I optimized protocols for oilseed poppy callus induction and regeneration across broad oilseed poppy cultivars, and established a necessary technical basis for future opium/oilseed poppy transformation and gene-editing applications. To address the threat of fungal pathogens Alternaria papavericola and Sclerotinia sclerotiorum, I established particular pathosystems. I have validated that spray-induced gene silencing (SIGS) is a viable, non-GMO disease control strategy for A. papavericola and S. sclerotiorum on oilseed poppy plants. I successfully demonstrated that exogenous application of doublestranded RNA (dsRNA) targeting essential pathogenicity genes significantly reduced infection severity and lesion development. In summary, these findings advance the mechanistic understanding of poppy innate immunity and provide practical biotechnological tools for enhancing disease resistance in modern agriculture.

Keywords

Papaver somniferum, Pattern trigger Immunity (PTI), Gen editing, Fungal pathogens, Spray Induced Gene Silencing (SIGs)

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 1. 6. 2026

Obhajoba závěrečné práce

• Vedoucí: doc. Ing. Martin Janda, Ph.D.

JIHOČESKÁ UNIVERZITA V ČESKÝCH BUDĚJOVICÍCH

Přírodovědecká fakulta

Doktorský studijní program / obor:
Integrative biology / Integrative biology