Advances in Biosynthesis and Biological Functions of Proanthocyanidins in Horticultural Plants

Abstract

Proanthocyanidins are colorless flavonoid polymers condensed from flavan-3-ol units. They are essential secondary plant metabolites that contribute to the nutritional value and sensory quality of many fruits and the related processed products. Mounting evidence has shown that the accumulation of proanthocyanidins is associated with the resistance of plants against a broad spectrum of abiotic and biotic stress conditions. The biosynthesis of proanthocyanidins has been examined extensively, allowing for identifying and characterizing the key regulators controlling the biosynthetic pathway in many plants. New findings revealed that these specific regulators were involved in the proanthocyanidins biosynthetic network in response to various environmental conditions. This paper reviews the current knowledge regarding the control of key regulators in the underlying proanthocyanidins biosynthetic and molecular mechanisms in response to environmental stress. Furthermore, it discusses the directions for future research on the metabolic engineering of proanthocyanidins production to improve food and fruit crop quality.

Proanthocyanidins and Where to Find Them: A Meta-Analytic Approach to Investigate Their Chemistry, Biosynthesis, Distribution, and Effect on Human Health

“…Indeed, since plants are sessile organisms, they are subjected to a series of menaces derived not only from adverse environmental conditions, but also from animals, insects, fungi, bacteria, or other plants. Generally, these phenomena lead to the overproduction of reactive oxygen (ROS) and nitrogen (RNS) species, and then in oxidative stress [ 44 ]. ROS and RNS are very dangerous molecules for both animal and plant cells, as they are highly reactive and capable of compromising the normal function of a large class of biomolecules, including proteins, lipids, and nucleic acids [ 15 , 44 ].…”

“…Generally, these phenomena lead to the overproduction of reactive oxygen (ROS) and nitrogen (RNS) species, and then in oxidative stress [ 44 ]. ROS and RNS are very dangerous molecules for both animal and plant cells, as they are highly reactive and capable of compromising the normal function of a large class of biomolecules, including proteins, lipids, and nucleic acids [ 15 , 44 ]. In order to counteract the overproduction of ROS and RNS, during both biotic and abiotic stresses, the normal physiological functions of plants are alternated, and in particular, specific metabolic pathways are activated, resulting in the biosynthesis of both non-enzymatic antioxidants, such as ascorbic acid, flavonols, glutathione and various pigments, and/or enzymatic defenses [ 15 ].…”

Metabolite Profiling and Transcriptome Analysis Provide Insight into Seed Coat Color in Brassica juncea

“…In Brassica species, the seed pigments are predominantly flavonoid metabolites, i.e., flavonols, anthocyanins, and proanthocyanidins (PAs), which are mainly produced through the pathway of flavonoid biosynthesis [10,17,18]. PAs are the most numerous and widely distributed polyphenols in plants and determine seed coat color in Arabidopsis thaliana [9][10][11], Medicago truncatula [19,20], sheepgrass (Leymus chinensis) [21], and B. napus [13,16,22].…”

EkFLS overexpression promotes flavonoid accumulation and abiotic stress tolerance in plant

“…The biosynthesis of bioactive compounds in plants can be increased or induced through biocatalytic and chemical approaches (Pablo et al, 2019; Zhang & Schrader, 2017). Plant hormones are tightly connected with flavonoid biosynthesis and able to influence their changes under abiotic stresses (Yu et al, 2020). Methyl jasmonate (MeJA), as a new type of plant endogenous hormone, can participate in the anabolic pathway of plant flavonoids.…”