Plant secondary metabolite citral interferes with Phytophthora capsici virulence by manipulating the expression of effector genes

Abstract

Phytophthora capsici is a notorious pathogen that infects various economically important plants and causes serious threats to agriculture worldwide. Plants deploy a variety of plant secondary metabolites to fend off pathogen attacks, but the molecular mechanisms are largely unknown. In this study, we screened 11 plant secondary metabolites to evaluate their biofumigation effects against P. capsici, and found that citral, carvacrol, and trans-2-decenal exhibited strong antimicrobial effects. Intriguingly, a low concentration of citral was effective in restricting P. capsici infection in Nicotiana benthamiana, but it was unable to inhibit the mycelial growth. A high concentration of citral affected the mycelial growth and morphology, zoospore germination, and cell membrane permeability of P. capsici. Further investigations showed that citral did not induce expression of tested plant immunity-related genes and reactive oxygen species (ROS) production, suggesting that a low concentration of citral could not trigger plant immunity. Moreover, RNA-Seq analysis showed that citral treatment regulated the expression of some P. capsici effector genes such as RxLR genes and P. cactorum-fragaria (PCF)/small cysteine-rich (SCR)74-like genes during the infection process, which was also verified by reverse transcription-quantitative PCR assay. Five candidate effector genes suppressed by citral significantly facilitated P. capsici infection in N. benthamiana or inhibited ROS triggered by flg22, suggesting that they were virulence factors of P. capsici. Together, our results revealed that plant-derived citral exhibited excellent inhibitory efficacy against P. capsici by suppressing vegetative growth and manipulating expression of effector genes, which provides a promising application of citral for controlling Phytophthora blight.

Synthesis, antifungal activity and action mechanism of novel citral amide derivatives against Rhizoctonia solani

“…32 In addition, citral has remarkable broad-spectrum inhibitory activities against bacteria and fungi. [21][22][23] Importantly, we found that citral exhibited good antifungal activity against R. solani with an EC 50 value of 28.86 mg L −1 (Table 1), indicating that citral could be used as a raw material to develop new antifungal agents against R. solani. Therefore, a new series of novel amide compounds bound to the citral skeleton and amide group were designed and synthesized to obtain new agents with good antifungal activity against R. solani; the general pathways are shown in Fig.…”

“…[17][18][19] Owing to the presence of multiple unsaturated groups, citral has been investigated as a model compound for various reactions. 20 In addition, citral and its derivatives possess broad-spectrum antifungal activity against various plant pathogens, such as R. solani, Penicillium digitatum and Botrytis cinerea, [21][22][23][24] therefore citral can be used as an ideal lead structure for the development of antifungal agents owing to its original fungicidal effect.…”

Biofumigation by Mustard Plants as an Application for Controlling Postharvest Gray Mold in Apple Fruits

“…In recent years, there has been increasing interest in using microbial antagonists and natural plant products for the biological control of fruit postharvest diseases [38][39][40][41]. Some natural plant products, such as citral, jasmonates, benzaldehyde, and ethanol, have been found to have potential antimicrobial activity against postharvest pathogens [42], but research on these is still limited. In this study, a mustard cultivar called Dilong-1 was found to greatly suppress the mycelial growth of B. cinerea compared to other cultivars.…”

Harnessing Plant’s Arsenal: Essential Oils as Promising Tools for Sustainable Management of Potato Late Blight Disease Caused by Phytophthora infestans—A Comprehensive Review

“…Yet, these assumptions open up certain attempts to understand. Lastly, citral inhibited the expression of certain effector genes and could decrease virulence of P. capsici towards its host [184]. This raises a whole new field of comprehension on a transcriptomic level about pathogen-host interactions modulated by EOC.…”