Effects Of Exogenous Polyamines On Stylar Protein Expressions During Pollination And Fertilization Of Yali Pear

Yali Pear belongs to the kind of gametophytic self-incompatibility, the percentage of self-pollinated fruit set is extremely low. The results based on our previous research show that, sprayed polyamine in a concentrations range at florescence could break self-incompatibility of Yali pear. However, there has been no further study on stylar protein expression during pollination and fertilization which is an important link to self-fertility. In this paper, the effects of exogenous polyamines on stylar protein expression of the Yali pear were studied by two-dimensional gel electrophoresis (2-DE) and mass spectrum analysis technology. The main results were as follows:1. The percentage of self-pollinated fruit set was significantly increased by spraying different kind of exogenous polyamines in Yali pear. The best effects of exogenous polyamines are Put(0.25mmol/L), Spd(0.25mmol/L) and Spm(0.05mmol/L).2. Style extracts after exogenous polyamines treatment on in vitro pollen germination were examined with Yali pear. The results showed that pollen germination rate in vitro and the pollen tube length were significantly increased after suitable concentration of polyamines treatment. The best effects of exogenous polyamines are Put(0.25mmol/L), Spd(0.25mmol/L) and Spm(0.05mmol/L).3. By examining the dynamic growth process of pollen tube under fluorescence microscope, pollen tube stopped growth and enlarged at middle of the style 72 hours after self-pollination. Three kinds of polyamines stimulated pollen tube growth in Yali pear. The numbers of pollen tube reached to the bottom of style treated by 0.25mmol/L Spd. were the best. The ovaries after 0.25mmol/L Spd treatment were observed by paraffine method. The results showed that 72 hours after pollination, pollen tube get into ovule and released sperms.4. The changes of stylar soluble proteins were detected by SDS-PAGE. The results showed that both quantity and quality of protein differed in the stage of development of style in Yali pear. Three protein bands (27.0kDa, 37.2kD and 40.0kDa) were differentially expressed in bud stage. Compared to cross-pollination style of Yali pear, four new protein bands (18.0, 22.5kDa, 27.4kDa and 30.0kDa) were specifically expressed in self-pollination style of Yali pear at 3rd day. The proteins were further separated by 2D-PAGE. The results showed that protein A (27.0kDa/pI4.8) was specifically expressed in bud stage. The expressions of protein B (28.0kDa/pI5.7) increased during stylar development and maturation. The expressions of protein C (28.5kDa/pI5.7) were decreased in coss-pollination style with the time.5. Compared to self-pollination style of Yali pear, two new protein bands (22.5kDa, and 30.0kDa) were not detected in 0.25mmol/L Spd treatment style of Yali pear at 3rd day. The proteins were further separated by 2D-PAGE. The results showed that the expressions of protein B decreased and the expressions of protein C disappeared in Spd treatment style with the time. Protein D (22.0kDa/pI5.3) was expressed both in self-pollination style and Spd treatment style at 1st day. And it disappeared in Spd treatment style at 2nd and 3rd day.6. A specific protein showed some similarity with know protein in the database, it is putative self-incompatibility protein. The function of identified protein related to S-allel.