Emerging roles for microtubules in angiosperm pollen tube growth highlight new research cues

Onelli, Elisabetta; Idilli, Aurora; Moscatelli, Alessandra

doi:10.3389/fpls.2015.00051

Cited by 25 publications

(20 citation statements)

References 222 publications

(342 reference statements)

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“…During pollen tube growth, the establishment of a narrow growth site at the plasma membrane of growing tip requiring continuous targeting of Golgi-derived vesicles to this site and their fusion with the plasma membrane is essential for proper polarized cell growth (Emons and Ketelaar 2009;Zársky et al 2009;Onelli et al 2015). Highly active vesicle trafficking processes also occur in microspores and tapetal cells during pollen development (Scott et al 2004).…”

Section: Introductionmentioning

confidence: 96%

Analysis of EXO70C2 expression revealed its specific association with late stages of pollen development

Lai

2015

Plant Cell Tiss Organ Cult

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Exocyst is an octameric protein complex that mediates the tethering of secretory vesicles at the plasma membrane for exocytosis. In this study, a 1136 bp promoter fragment of exocyst subunit exo70 family protein C2 (EXO70C2) was fused with the b-glucuronidase (GUS) reporter gene and introduced into Arabidopsis thaliana via Agrobacterium tumefaciens. Detail histochemical analysis of EXO70C2-GUS expression in T 3 transgenic A. thaliana lines revealed a strong GUS activity at late stages of pollen development. Strong GUS signals were visible from post meiotic pollen, mature pollen and pollen release stages. There was no detectable expression of EXO70C2-GUS during early pollen development and meiosis stages. Consistent with the GUS assay, EXO70C2 transcript profiling using real-time PCR analysis also showed high expression of EXO70C2 at these late stages of pollen development. Further RNA in situ hybridisation revealed the presence of EXO70C2 signals in pollen and as well as anther tapetum. Taken together, these results indicate that, EXO70C2 is specifically expressed in pollen and anther tapetum during the late stages of pollen development, suggesting its function in regulating essential secretory vesicles to support pollen maturation.

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Section: Introductionmentioning

confidence: 96%

Analysis of EXO70C2 expression revealed its specific association with late stages of pollen development

Lai

2015

Plant Cell Tiss Organ Cult

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“…In pollen tubes, MTs control movement of the male germ unit [ 21 ] and positioning of large vacuoles in the distal regions of the tube [ 22 ]. More recently, it was reported that MTs also play a role in exocytosis in the central region of the tip and in endosome trafficking [ 7 , 19 ]. Specifically, MT perturbation by nocodazole delayed transport of endocytic vesicles to the vacuoles [ 7 ] and redirected the endocytosed material to the Golgi apparatus, suggesting that MTs are involved in transport of endosomes towards vacuoles [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Microtubules play a role in trafficking prevacuolar compartments to vacuoles in tobacco pollen tubes

et al. 2018

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Fine regulation of exocytosis and endocytosis plays a basic role in pollen tube growth. Excess plasma membrane secreted during pollen tube elongation is known to be retrieved by endocytosis and partially reused in secretory pathways through the Golgi apparatus. Dissection of endocytosis has enabled distinct degradation pathways to be identified in tobacco pollen tubes and has shown that microtubules influence the transport of plasma membrane internalized in the tip region to vacuoles. Here, we used different drugs affecting the polymerization state of microtubules together with SYP21, a marker of prevacuolar compartments, to characterize trafficking of prevacuolar compartments in Nicotiana tabacum pollen tubes. Ultrastructural and biochemical analysis showed that microtubules bind SYP21-positive microsomes. Transient transformation of pollen tubes with LAT52-YFP-SYP21 revealed that microtubules play a key role in the delivery of prevacuolar compartments to tubular vacuoles.

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“…Another plant structure characterized by polarized fast growth is the pollen tube. MTs play a role in secretion and endocytosis, acting as tracks for vesicular transport and deposition of proteins/lipids at the tip membrane [ 27 ]. Interestingly, overexpression of a Picea wilsonii pollen-specific alpha tubulin gene increases pollen tube growth rate in Arabidopsis [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Evolutionary characterization and transcript profiling of β-tubulin genes in flax (Linum usitatissimum L.) during plant development

et al. 2017

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BackgroundMicrotubules, polymerized from alpha and beta-tubulin monomers, play a fundamental role in plant morphogenesis, determining the cell division plane, the direction of cell expansion and the deposition of cell wall material. During polarized pollen tube elongation, microtubules serve as tracks for vesicular transport and deposition of proteins/lipids at the tip membrane. Such functions are controlled by cortical microtubule arrays. Aim of this study was to first characterize the flax β-tubulin family by sequence and phylogenetic analysis and to investigate differential expression of β-tubulin genes possibly related to fibre elongation and to flower development.ResultsWe report the cloning and characterization of the complete flax β-tubulin gene family: exon-intron organization, duplicated gene comparison, phylogenetic analysis and expression pattern during stem and hypocotyl elongation and during flower development. Sequence analysis of the fourteen expressed β-tubulin genes revealed that the recent whole genome duplication of the flax genome was followed by massive retention of duplicated tubulin genes. Expression analysis showed that β-tubulin mRNA profiles gradually changed along with phloem fibre development in both the stem and hypocotyl. In flowers, changes in relative tubulin transcript levels took place at anthesis in anthers, but not in carpels.ConclusionsPhylogenetic analysis supports the origin of extant plant β-tubulin genes from four ancestral genes pre-dating angiosperm separation. Expression analysis suggests that particular tubulin subpopulations are more suitable to sustain different microtubule functions such as cell elongation, cell wall thickening or pollen tube growth. Tubulin genes possibly related to different microtubule functions were identified as candidate for more detailed studies.Electronic supplementary materialThe online version of this article (10.1186/s12870-017-1186-0) contains supplementary material, which is available to authorized users.

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Emerging roles for microtubules in angiosperm pollen tube growth highlight new research cues

Cited by 25 publications

References 222 publications

Analysis of EXO70C2 expression revealed its specific association with late stages of pollen development

Analysis of EXO70C2 expression revealed its specific association with late stages of pollen development

Microtubules play a role in trafficking prevacuolar compartments to vacuoles in tobacco pollen tubes

Evolutionary characterization and transcript profiling of β-tubulin genes in flax (Linum usitatissimum L.) during plant development

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