Modulation of Phytoalexin Biosynthesis in Engineered Plants for Disease Resistance

Abstract

Phytoalexins are antimicrobial substances of low molecular weight produced by plants in response to infection or stress, which form part of their active defense mechanisms. Starting in the 1950’s, research on phytoalexins has begun with biochemistry and bio-organic chemistry, resulting in the determination of their structure, their biological activity as well as mechanisms of their synthesis and their catabolism by microorganisms. Elucidation of the biosynthesis of numerous phytoalexins has permitted the use of molecular biology tools for the exploration of the genes encoding enzymes of their synthesis pathways and their regulators. Genetic manipulation of phytoalexins has been investigated to increase the disease resistance of plants. The first example of a disease resistance resulting from foreign phytoalexin expression in a novel plant has concerned a phytoalexin from grapevine which was transferred to tobacco. Transformations were then operated to investigate the potential of other phytoalexin biosynthetic genes to confer resistance to pathogens. Unexpectedly, engineering phytoalexins for disease resistance in plants seem to have been limited to exploiting only a few phytoalexin biosynthetic genes, especially those encoding stilbenes and some isoflavonoids. Research has rather focused on indirect approaches which allow modulation of the accumulation of phytoalexin employing transcriptional regulators or components of upstream regulatory pathways. Genetic approaches using gain- or less-of functions in phytoalexin engineering together with modulation of phytoalexin accumulation through molecular engineering of plant hormones and defense-related marker and elicitor genes have been reviewed.

MALDI Mass Spectrometry Imaging for the Simultaneous Location of Resveratrol, Pterostilbene and Viniferins on Grapevine Leaves

“…Phytoalexins are of great interest because they are biosynthetized in response to biotic or abiotic stress. They are also well known for inducing an antifungal activity [13][14][15][16][17][18] and, for example, we observed by MSI experiment a co-localization of resveratrol and pterostilbene (trimethoxystilbene) at the infection site on the leaf abaxial side (Cabernet Sauvignon) [12] after infection by downy mildew. MSI allowed the identification and mapping of resveratrol and pterostilbene but the biosynthesis of some other stilbenes is also expected to be induced in grapevine leaves and even berries in response to pathogen infection or UV irradiation [19][20][21].…”

Evaluasi Resistensi Progeni Anggrek Phalaenopsis terhadap Penyakit Busuk Lunak (Pseudomonas viridiflava)

“…Pada penyakit busuk lunak bakteri, beberapa laporan menyebutkan bahwa mekanisme ketahanan disebabkan oleh karakteristik genotipe tanaman yang mampu memproduksi fitoaleksin yang dapat menghambat atau membunuh patogen (Jeandet et al 2013). Mekanisme ketahanan tanaman terhadap P. viridiflava hingga saat ini belum terungkap sempurna.…”

Grapevine Biotechnology: Molecular Approaches Underlying Abiotic and Biotic Stress Responses

“…STS, the key enzyme in resveratrol synthesis, uses as substrates precursor molecules that are present throughout the plant kingdom. Therefore, the introduction of a single gene is sufficient to synthesize resveratrol in heterologous plant species [53].…”