Tubulin Isotypes in Rye Roots Are Altered during Cold Acclimation

Area of Science:

• Plant biology
• Cellular and molecular biology
• Biochemistry

Background:

• Cortical microtubule cold stability in winter rye root tips is influenced by growth temperature.
• A hypothesis suggests that changes in tubulin isotypes at different temperatures affect microtubule stability.
• Investigating tubulin isotype composition is crucial for understanding plant cold acclimation mechanisms.

Purpose of the Study:

• To investigate the first part of the hypothesis: whether different tubulin isotypes are present at different growth temperatures in winter rye.
• To analyze changes in alpha- and beta-tubulin isotype composition during cold acclimation.

Main Methods:

• Seedlings of winter rye (Secale cereale L. cv Puma) were grown at 22°C (nonacclimated) and then cold-acclimated at 4°C for 2 or 4 days.
• Protein extracts from root tips were analyzed using two-dimensional polyacrylamide gel electrophoresis.
• Immunoblots were probed with monoclonal antibodies specific to alpha- and beta-tubulin.

Main Results:

• At least six alpha-tubulin and seven beta-tubulin isotypes were detected in both nonacclimated and cold-acclimated root extracts.
• Significant changes in the electrophoretic mobility and number of both alpha- and beta-tubulin isotypes were observed after 2 days at 4°C.
• Further alterations in tubulin composition occurred after 4 days at 4°C, with more pronounced changes noted in alpha-tubulin.

Conclusions:

• Cold acclimation induces changes in the composition of alpha- and beta-tubulin isotypes in winter rye root tips.
• These observed changes in tubulin isotypes support the hypothesis that altered isotype presence contributes to microtubule cold stability.
• Alpha-tubulin appears to be more responsive to cold acclimation than beta-tubulin in this species.