Comparative analysis of stamen polypeptides of a rapeseed cultivar, Regent, a CMS polima line, and temperature-restored male-fertile polima line

Abstract

Polypeptides were extracted from stamens of a rapeseed (Brassica napus) cultivar, Regent, a near isogenic male-sterile line, Polima-R7 (Pol-R7), and a high-temperature-restored malefertile Pol-R7 (TR) and subsequently separated by two-dimensional isoelectric focusing-polyacrylamide gel electrophoresis under denaturing conditions. Four variable polypeptides with a pI around 6 were observed. Two stamen polypeptides (40000 Da, 38000 Da) were unique to Regent, and the other two (32000 Da, 30000 Da) were unique to the male-sterile Pol-R7. When the male-sterile Pol-R7 was treated with day/night temperatures of 30°/24° C for 7–10 days prior to flowering, both polypeptides unique to Regent reappeared, while the smaller polypeptides disappeared. Temperature-restored male-fertile Pol-R7 (TR) produced fertile pollen, while its short stamen filaments resembled those of the male-sterile Pol-R7. These changes in protein expression may be causally related to the CMS phenotype.