Role Of Phenylpropanoids Research Articles

Role of Phenylpropanoids and Flavonoids in Plant Defense Mechanism

Phenylpropanoids and flavonoids are specialized metabolites that play a crucial role in plant defenses against biotic and abiotic stresses. Secondary metabolites in plants, such as phenylpropanoids, flavonoids, lignins, monolignols, phenolic acids, stilbenes and coumarins, play a significant role in biotic and abiotic stress responses and interactions with their environment. Under stress-free conditions, flavonoids influence pollen tube growth, seed maturation, dormancy, and the longevity of plant reproductive organs and seeds. Under adverse abiotic conditions, flavonoids can mediate defense responses, such as the accumulation of flavonoids in leaves and glandular trichomes. Metabolomics has identified specialized PPP metabolites correlated with plant resistance to fungi and oomycetes. However, the correlation can be in opposite directions depending on the pathogen and a systemic approach is required to achieve increased resistance without decreasing resistance to another pathogen. The PAL gene is located upstream in the PPP pathway and phenylpropanoids and flavonoids have antifungal activity against Fusarium oxysporum, Rhizoctonia solani and Alternaria alternata. Phenylpropanoids have been studied in vitro to develop biological alternatives to synthetic phytoprotectants but the host's defense system is the most effective mode of action. Post-inoculation transcriptomic shifts reveal that some genes encoding enzymes in the PPP are rapidly activated, while others are induced later in the infection response. Insects are the most problematic macroscopic pests on cultivated plants and plants' natural defense mechanisms against herbivores include releasing volatile organic compounds, attracting enemies and producing phenylpropanoids and flavonoids. Increasing the content of flavonoids in infested plants can reduce the population of insects that cause damage to plants and spread viruses. Plant-environment interaction, mediated by secondary metabolites like phenylpropanoids and flavonoids, leads to diversity in gene structures. Systemic biology approach will be realized through sequencing, structural elucidation, and analytical tools. Model plants and crops can be used for exploration.

Role of Phenylpropanoids and Flavonoids in Plant Resistance to Pests and Diseases

Phenylpropanoids and flavonoids are specialized metabolites frequently reported as involved in plant defense to biotic or abiotic stresses. Their biosynthetic accumulation may be constitutive and/or induced in response to external stimuli. They may participate in plant signaling driving plant defense responses, act as a physical or chemical barrier to prevent invasion, or as a direct toxic weapon against microbial or insect targets. Their protective action is described as the combinatory effect of their localization during the host's interaction with aggressors, their sustained availability, and the predominance of specific compounds or synergy with others. Their biosynthesis and regulation are partly deciphered; however, a lot of gaps in knowledge remain to be filled. Their mode of action on microorganisms and insects probably arises from an interference with important cellular machineries and structures, yet this is not fully understood for all type of pests and pathogens. We present here an overview of advances in the state of the art for both phenylpropanoids and flavonoids with the objective of paving the way for plant breeders looking for natural sources of resistance to improve plant varieties. Examples are provided for all types of microorganisms and insects that are targeted in crop protection. For this purpose, fields of phytopathology, phytochemistry, and human health were explored.

Investigating the roles of phenylpropanoids in the growth and development of Zea mays L.

The Poaceae includes some of the most important food, fiber, and bio-fuel crops. While there have been many studies investigating the function of phenylpropanoids in this family, most of our understanding is based on correlative data rather than experimental evidence. The current study was conducted to evaluate the roles of phenylpropanoids in the growth and development of Zea mays and to develop an experimental model for further investigations. Z. mays seedlings were grown in vitro with various concentrations of the competitive phenylalanine ammonia lyase inhibitor, 2-aminoindane-2-phosphonic acid (AIP). Ferulic acid, a downstream biosynthetic product, was added to determine if it could rescue the induced phenotypes. At lower concentrations of AIP, plants exhibited elongated roots and shoots, but at higher concentrations, growth was extremely stunted. At the cellular level, the epidermal cells of roots cultured with AIP exhibited a loss of intercellular adhesion and organization, and their cell walls were more readily degraded by enzymatic digestion. These characteristics were accompanied by significant reductions in primary cell wall autofluorescence, indicating that less ferulic acid and other phenolics were incorporated in the cell wall. The majority of these symptoms could be partially or entirely rescued by ferulic acid, providing further evidence that these differences were due to the inhibition of phenylpropanoid biosynthesis. This study provides experimental evidence supporting and expanding upon hypothesized functions of phenylpropanoids in the growth and development of Z. mays and provides an experimental system for further investigations in the Poaceae and other taxonomic groups.

Genome‐wide analysis of phenylpropanoid defence pathways

Phenylpropanoids can function as preformed and inducible antimicrobial compounds, as well as signal molecules, in plant-microbe interactions. Since we last reviewed the field 8 years ago, there has been a huge increase in our understanding of the genes of phenylpropanoid biosynthesis and their regulation, brought about largely by advances in genome technology, from whole-genome sequencing to massively parallel gene expression profiling. Here, we present an overview of the biosynthesis and roles of phenylpropanoids in plant defence, together with an analysis of confirmed and predicted phenylpropanoid pathway genes in the sequenced genomes of 11 plant species. Examples are provided of phylogenetic and expression clustering analyses, and the large body of underlying genomic data is provided through a website accessible from the article.