Characterization of cDNAs encoding CuZn-superoxide dismutases in Scots pine

Area of Science:

• Plant molecular biology
• Biochemistry
• Genetics

Background:

• Superoxide dismutases (SODs) are crucial antioxidant enzymes in plants, protecting against oxidative stress.
• CuZn-SODs are a significant class of SOD isozymes found across plant species.
• Understanding SOD gene families in conifers like Scots pine (Pinus sylvestris L.) is important for plant stress response research.

Purpose of the Study:

• To isolate and characterize cDNA clones encoding cytosolic and chloroplastic superoxide dismutases (SOD) in Scots pine.
• To analyze the homology and expression patterns of these SOD isozymes.
• To investigate the genetic basis of CuZn-SOD in Scots pine.

Main Methods:

• Screening of a Scots pine cDNA library using heterologous probes from tomato.
• Subcloning, mapping, and sequencing of positive cDNA clones.
• Northern and Southern blot hybridizations to analyze gene expression and family size.

Main Results:

• Isolation of full-length and partial cDNA clones for cytosolic (PS3) and chloroplastic (PST13) SODs.
• High amino acid homology (85% and 93%) of isolated clones with known angiosperm and pea/tomato SODs, respectively.
• Differential expression of cytosolic and chloroplastic CuZn-SOD in Scots pine organs.
• Confirmation of CuZn-SODs belonging to a multigene family in Scots pine.

Conclusions:

• Scots pine possesses distinct genes for cytosolic and chloroplastic CuZn-SODs.
• The identified SOD sequences are conserved among plant species.
• CuZn-SOD expression varies across different tissues in Scots pine, suggesting specialized roles.
• Scots pine harbors a multigene family for CuZn-SODs, similar to other plants.