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ARS Home » Pacific West Area » Pullman, Washington » Plant Germplasm Introduction and Testing Research » Research » Publications at this Location » Publication #297693
Title: Molecular and cellular characterization of the tomato pollen profilin, LePro1

Author
item Yu, Long-Xi
item PARTHASARATHY, MANDAYAM - Cornell University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2013
Publication Date: 1/21/2014
Citation: Yu, L., Parthasarathy, M. 2014. Molecular and cellular characterization of the tomato pollen profilin, LePro1. PLoS One. DOI:10.1371/journal.pone.0086505.

Interpretive Summary: We reported the results for a fundamental study of an tomato actin-binding protein, LePro1 using multiple approaches. First, we examined the gene expression pattern during pollen development and found that LePro1 is a late pollen-specific protein. Second, we used a green flourescence protein reporter fused with LePro1 and investigated the cellular localization of the protein. A specific localization was observed in the generative cell but not in the vegetative nucleus. Third, using antisense RNA, we successfully knocked down the expression of LePro1 in tomato plants using stable transformation. Study of antisense lines showed significant down-regulation of LePro1 in pollen resulting in poor pollen germination and abnormal pollen tube growth. Our results suggest that LePro1 plays an essential role in pollen hydration, germination and tube growth.

Technical Abstract: Profilin is an actin-binding protein involved in the dynamic turnover and restructuring of the actin cytoskeleton in all eukaryotic cells. We previously cloned a profilin gene, designated as LePro1 from tomato pollen. To investigate its biological role, in the present study, We investigated the temporal and spatial expression of LePro1 during pollen development using RNA blot and in situ hybridization. We found that the transcript was only detected at late stages during microsporogenesis and pollen maturation. We used a GFP reporter fused with LePro1 and transiently expressed in tobacco pollen cells, and observed a uniform distribution of the fusion protein in the entire cytoplasm of the pollen tube including the clear zone at the tip. A specific localization was observed in the generative cell but not in the vegetative nucleus. Using antisense RNA, we successfully knocked down the expression of LePro1 in tomato plants using stable transformation, and obtained two antisense lines, A2 and A3 showing significant down-regulation of LePro1 in pollen resulting in poor pollen germination and abnormal pollen tube growth. A disorganized F-actin distribution was observed in the antisense pollen. Down-regulation of LePro1 also appeared to affect hydration of pollen deposited on the stigma and arrested pollen tube elongation in the style, thereby affecting fertilization. Our results suggest that LePro1 plays an essential role in pollen hydration, germination and tube growth.