A Preliminary Study On The Function Of Type Receptor Protein In Pollen Tube Of Arabidopsis Thaliana

The quality of agricultural raw materials is a key factor to determine the quality of food processing, and the crop varieties are the most critical factor in determining the crop quality. Crossbreeding was the major method to improve the quality of agricultural products, but a phenomenon called cross barrier shows the low rate of fertility always occurs in the hybrid F1generation. In the double fertilization process, the angiosperm evolves a precise regulatory pathway to control the growth of the pollen tube toward the embryo sac, entry into the micropyle and releasing the sperms to complete double fertilization. While cross barrier often occurs in the process of fertilization, especially during pollen tube receiving signals which guide the growing pollen tubes.Arabidopsis as a model plant is an ideal material in the study of the directed pollen tube growth. Research results from the Arabidopsis may be applied to or direct food crops and cash crops, thereby improving the quality of food raw materials and promoting the development of the food industry. In Arabidopsis, the pollen tube signal-oriented process is more complex, involving signaling molecules and genes, so less research.Receptor-like proteins (RPs) are cell surface receptor that typically consist of an extracellular leucine-rich repeat domain, a transmembrane domain, and a short cytoplasimatic tail. In several plant species, RPs have been found to play a role in disease resistance, such as the tomato Cf proteins. In total,57RP genes have been identified in the Arabidopsis genome and a genome-wide collection of T-DNA insertion lines was assembled. Among them, the extensively studied CLAVATA2(RP10) and TMM (RP17), have been shown to play an important role in plant growth and development process. There are several RPs expressed in pollen, but the function has not been identified. Therefore, we are to indentify receptor-like protein that is involved in pollen tube guidance by genetic analysis.Candidate RP genes are collected from several pollen microarray data published and Genevestigator database. And the T-DNA insertion mutants are obtained from ABRC stock center. Homozygous mutants are characterized through PCR analysis. RT-PCR analysis is performed to confirm the RP genes transcription level. In order to obtain the double-mutants which have phenotype, I use the method of hybridization between mutants. Then I find rp5rp57, comparing to fertilization rate of wild-type 90.27%, the fertilization rate of rp5rp57only64%. Pollen tube staining experiments show that wild-type can smoothly entry into the micropyle and reach the embryo sac, but rp5rp57is failed. Obviously, during the process of pollen tube perception and recognition the signal of embryo sac, there is a problem in rp5rp57. This phenotype analysis explains why the fertilization rate of rp5rp57lower than wild-type and shows two RPs are involved in pollen tube guidance.