Primary structure and expression of mRNAs encoding basic chitinase and 1,3-beta-glucanase in potato

Area of Science:

• Plant Molecular Biology
• Biochemistry
• Plant Pathology

Background:

• Potato plants (Solanum tuberosum L.) exhibit increased chitinase and 1,3-beta-glucanase activities in response to late blight fungus (Phytophthora infestans) infection or elicitor treatment.
• These enzymes are crucial for plant defense mechanisms against pathogens.

Purpose of the Study:

• To characterize the genes encoding class I chitinase and 1,3-beta-glucanase in potato.
• To investigate the regulation and expression patterns of these defense-related genes.

Main Methods:

• Complementary DNA (cDNA) isolation and sequence analysis.
• RNA blot hybridization to study gene expression.
• DNA blot analysis to assess gene families.

Main Results:

• Isolated cDNAs for basic (class I) chitinase and 1,3-beta-glucanase, revealing structural features including signal peptides, catalytic domains, and C-terminal extensions.
• Demonstrated coordinate induction of chitinase and 1,3-beta-glucanase genes in response to infection, elicitor, ethylene, and wounding.
• Identified developmental and organ-specific expression patterns, with higher mRNA levels in older leaves, stems, and roots, and differential expression in young leaves and stems.
• DNA blot analysis indicated complex gene families encode these enzymes in potato.

Conclusions:

• Potato chitinase and 1,3-beta-glucanase genes are strongly induced by biotic and abiotic stress factors.
• Gene expression is regulated in a complex, tissue-specific, and developmental manner.
• Potato possesses intricate gene families for chitinase and 1,3-beta-glucanase, reflecting their importance in plant defense.