Overexpression of Tomato Pollen Receptor Kinase Rewires Pollen Tube Growth to Blebbing Mode
Sep 24, 2014 Email"> PrintText Size
Pollen tube is a special plant cell which grows within pistil in a tubular growth mode for delivering sperm cells to egg. This process is essential for seed formation of flowering plants. Recently, a research group led by Dr. TANG Weihua, from Shanghai Institute of Plant Physiology and Ecology (SIPPE), Shanghai Institutes for Biological Sciences (SIBS) of Chinese Academy of Sciences (CAS), presents the evidence that the tubular growth mode of pollen tube cell can be transformed to a blebbing mode by overexpression of a single molecule namely LePRK1 or LePRK1ΔECD.
Plant receptors like kinases (RLKs) are membrane-localized proteins with serine/threonine kinase activity and regulate diverse biological processes. LePRK1 is a receptor like kinase in tomato (Solanum lycopersicum) pollen tube. It is reported that LePRK1 interacts with KPP (kinase partner protein), which is an activator of small GTPase ROP. However, the physiological function of LePRK1 in tomato pollen tube was still unrevealed.
Pollen tubes normally grow in a tubular growth mode. The researchers from TANG’s lab, collaborating with Dr. Sheila McCormick at University of California, Berkeley, discovered that pollen tubes overexpressing LePRK1-eGFP or a truncated LePRK1 lacking its extracellular domain (LePRK1ΔECD-eGFP) extends their growth leading edges by forming blebs.
The blebbing growth mode has been previously reported in Dictyostelium and for Drosophila melanogaster stem cells. Coexpression of LePRK1-eGFP and tomato PLIM2a-mRFP suppressed pollen tube blebbing phenotype caused by LePRK1-eGFP overexpression, whereas pollen tubes coexpressing KPP, LePRK1 and PLIM2a restored the blebbing growth mode. The vitro biochemical assay showed that PLIM2a is an actin bundling protein and interacts with KPP in a Ca2+ dependent manner. Furthermore, Arabidopsis thaliana pollen tubes expressing LePRK1ΔECD-eGFP also grow in the blebbing mode.
The results uncover the physiological potential of the pollen tube cell: upon elevating the expression level of a single membrane-localized molecule (LePRK1 or LePRK1ΔECD), pollen tube can extend the growth leading edge by switching to a blebbing growth mode.
This research entitled “Overexpression of the Tomato Pollen Receptor Kinase LePRK1 Rewires Pollen Tube Growth to a Blebbing Mode” has been published online in the Plant Cell on September 5th, 2014.
This project was supported by the National Natural Science Foundation of China, the Ministry of Science and Technology of China and the US Department of Agriculture.
Overexpression of LePRK1 or LePRK1ΔECD rewires pollen tube tubular growth to a blebbing mode (Image by Dr. TANG Weihua 's research group)
Pollen tube is a special plant cell which grows within pistil in a tubular growth mode for delivering sperm cells to egg. This process is essential for seed formation of flowering plants. Recently, a research group led by Dr. TANG Weihua, from Shanghai Institute of Plant Physiology and Ecology (SIPPE), Shanghai Institutes for Biological Sciences (SIBS) of Chinese Academy of Sciences (CAS), presents the evidence that the tubular growth mode of pollen tube cell can be transformed to a blebbing mode by overexpression of a single molecule namely LePRK1 or LePRK1ΔECD.
Plant receptors like kinases (RLKs) are membrane-localized proteins with serine/threonine kinase activity and regulate diverse biological processes. LePRK1 is a receptor like kinase in tomato (Solanum lycopersicum) pollen tube. It is reported that LePRK1 interacts with KPP (kinase partner protein), which is an activator of small GTPase ROP. However, the physiological function of LePRK1 in tomato pollen tube was still unrevealed.
Pollen tubes normally grow in a tubular growth mode. The researchers from TANG’s lab, collaborating with Dr. Sheila McCormick at University of California, Berkeley, discovered that pollen tubes overexpressing LePRK1-eGFP or a truncated LePRK1 lacking its extracellular domain (LePRK1ΔECD-eGFP) extends their growth leading edges by forming blebs.
The blebbing growth mode has been previously reported in Dictyostelium and for Drosophila melanogaster stem cells. Coexpression of LePRK1-eGFP and tomato PLIM2a-mRFP suppressed pollen tube blebbing phenotype caused by LePRK1-eGFP overexpression, whereas pollen tubes coexpressing KPP, LePRK1 and PLIM2a restored the blebbing growth mode. The vitro biochemical assay showed that PLIM2a is an actin bundling protein and interacts with KPP in a Ca2+ dependent manner. Furthermore, Arabidopsis thaliana pollen tubes expressing LePRK1ΔECD-eGFP also grow in the blebbing mode.
The results uncover the physiological potential of the pollen tube cell: upon elevating the expression level of a single membrane-localized molecule (LePRK1 or LePRK1ΔECD), pollen tube can extend the growth leading edge by switching to a blebbing growth mode.
This research entitled “Overexpression of the Tomato Pollen Receptor Kinase LePRK1 Rewires Pollen Tube Growth to a Blebbing Mode” has been published online in the Plant Cell on September 5th, 2014.
This project was supported by the National Natural Science Foundation of China, the Ministry of Science and Technology of China and the US Department of Agriculture.
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