scholarly journals Regulation of Exocyst Function in Pollen Tube Growth by Phosphorylation of Exocyst Subunit EXO70C2

2021 ◽  
Vol 11 ◽  
Author(s):  
Antonietta Saccomanno ◽  
Martin Potocký ◽  
Přemysl Pejchar ◽  
Michal Hála ◽  
Hiromasa Shikata ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Negative Regulator ◽  
Tube Growth ◽  
Wild Type ◽  
Functional Studies ◽  
Tobacco Pollen ◽  
Pollen Tube Growth Rate ◽  
Mutant Cells ◽  
Dose Dependent

Exocyst is a heterooctameric protein complex crucial for the tethering of secretory vesicles to the plasma membrane during exocytosis. Compared to other eukaryotes, exocyst subunit EXO70 is represented by many isoforms in land plants whose cell biological and biological roles, as well as modes of regulation remain largely unknown. Here, we present data on the phospho-regulation of exocyst isoform EXO70C2, which we previously identified as a putative negative regulator of exocyst function in pollen tube growth. A comprehensive phosphoproteomic analysis revealed phosphorylation of EXO70C2 at multiple sites. We have now performed localization and functional studies of phospho-dead and phospho-mimetic variants of Arabidopsis EXO70C2 in transiently transformed tobacco pollen tubes and stably transformed Arabidopsis wild type and exo70C2 mutant plants. Our data reveal a dose-dependent effect of AtEXO70C2 overexpression on pollen tube growth rate and cellular architecture. We show that changes of the AtEXO70C2 phosphorylation status lead to distinct outcomes in wild type and exo70c2 mutant cells, suggesting a complex regulatory pattern. On the other side, phosphorylation does not affect the cytoplasmic localization of AtEXO70C2 or its interaction with putative secretion inhibitor ROH1 in the yeast two-hybrid system.

scholarly journals Extragenic suppressors of the arabidopsis zwi-3 mutation identify new genes that function in trichome branch formation and pollen tube growth

Development ◽  
1999 ◽  
Vol 126 (14) ◽  
pp. 3079-3088 ◽  
Author(s):  
S. Krishnakumar ◽  
D.G. Oppenheimer
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Mutational Analysis ◽  
Negative Regulator ◽  
Tube Growth ◽  
Tail Domain ◽  
Branch Number ◽  
New Genes ◽  
Allele Specific ◽  
Extragenic Suppressors

The plant cytoskeleton plays a pivotal role in determining the direction of cell wall expansion, and ultimately the cell's final shape. However, the mechanisms by which localized expansion events are initiated remain obscure. Mutational analysis of the trichome (plant hair) morphogenic pathway in Arabidopsis has identified at least eight genes that determine trichome branch number. One of these genes, ZWICHEL (ZWI), encodes a novel member of the kinesin superfamily of motor proteins. Mutations in the ZWI gene cause a reduction in the number of trichome branches. To identify additional genes involved in trichome branch initiation, we screened for extragenic suppressors of the zwi-3 mutation and isolated three suppressors that rescued the branch number defect of zwi-3. These suppressors define three genes, named suz, for suppressor of zwichel-3. All of the suppressors were shown to be allele specific. One of the suppressors, suz2, also rescued the trichome branch number defect of another branch mutant, furca1-2. Plants homozygous for suz2 have more than the wild-type number of trichome branches. This suggests that SUZ2 is a negative regulator of trichome branching and may interact with ZWI and FURCA1. The suz1 and suz3 mutants display no obvious phenotype in the absence of the zwi-3 mutation. The suz1 zwi-3 double mutants also exhibited a male-sterile phenotype due to a defect in pollen tube germination and growth, whereas both the suz1 and the zwi-3 single mutants are fertile. The synthetic male sterility of the suz1 zwi-3 double mutants suggests a role for SUZ1 and ZWI in pollen germination and pollen tube growth. DNA sequence analysis of the zwi-3 mutation indicated that only the tail domain of the zwi-3 protein would be expressed. Thus, the suz mutations show allele-specific suppression of a kinesin mutant that lacks the motor domain.

Actin and tubulin expression and isotype pattern during tobacco pollen tube growth

1996 ◽  
Vol 9 (5) ◽  
pp. 255-263 ◽  
Author(s):  
Outi Sorri ◽  
Helena Åström ◽  
Marjatta Raudaskoski
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tube Growth ◽  
Tobacco Pollen

scholarly journals Effects of Temperature and the Combination of Liquid Lime Sulfur and Fish Oil on Pollen Germination, Pollen Tube Growth, and Fruit Set in Apples

HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1277-1283 ◽  
Author(s):  
Keith Yoder ◽  
Rongcai Yuan ◽  
Leon Combs ◽  
Ross Byers ◽  
Jim McFerson ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Fruit Set ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Pollen Tube Growth Rate ◽  
Golden Delicious ◽  
Effects Of Temperature ◽  
Increasing Temperature

Effects of temperature and the combination of liquid lime sulfur (LLS) and fish oil (FO) applied during bloom on pollen germination and pollen tube growth in flowers and fruit set were examined in apples (Malus ×domestica Borkh.). Percent germination of pollen of ‘Manchurian’ crabapples and ‘Golden Delicious’ apple flowers on the stigmatic surface of ‘Golden Delicious’ pistils increased with increasing temperature from 13 to 29 °C in the first 24 and 48 h after pollination, respectively, but not thereafter. Pollen tube growth rate in the style increased quadratically with increasing temperature from 13 to 29 °C. ‘Manchurian’ was a more effective pollenizer of ‘Golden Delicious’ than was ‘Golden Delicious’ pollen. For example, at 24 or 29 °C, some ‘Manchurian’ pollen tubes grew to the base of ‘Golden Delicious’ styles by 24 h after pollination. On the other hand, no ‘Golden Delicious’ pollen tube grew to the base of a ‘Golden Delicious’ style regardless of temperature and time. Pollen tube growth rate in the style increased with increasing day/night temperature from 7/0 to 24/7 °C. The time required for pollen tubes to grow to the base of styles decreased with increasing day/night temperature from 13/2 to 24/7 °C. Only ≈36 h was required for pollen tubes to grow to the base of style at 24/7 °C, whereas pollen tubes grew very slowly and no pollen tubes grew to the base of style at 7/0 °C regardless of pollen source. LLS + FO, applied 4 or 24 h after pollination, inhibited pollen germination, pollen tube growth in the style, fertilization, and fruit set, but it had no effect when applied 48 h after pollination. These results suggest that LLS + FO applied at this bloom stage causes flower or fruit abscission most likely by inhibiting pollen germination, pollen tube growth in the style, and fertilization.

Drought limits pollen tube growth rate by altering carbohydrate metabolism in cotton (Gossypium hirsutum) pistils

Plant Science ◽  
2019 ◽  
Vol 286 ◽  
pp. 108-117 ◽  
Author(s):  
Wei Hu ◽  
Yu Liu ◽  
Dimitra A. Loka ◽  
Rizwan Zahoor ◽  
Shanshan Wang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Gossypium Hirsutum ◽  
Carbohydrate Metabolism ◽  
Pollen Tube Growth ◽  
Tube Growth ◽  
Pollen Tube Growth Rate

scholarly journals Apple Pollen Tube Growth Rates Are Regulated by Parentage and Environment

2016 ◽  
Vol 141 (6) ◽  
pp. 548-554 ◽  
Author(s):  
Candace N. DeLong ◽  
Keith S. Yoder ◽  
Leon Combs ◽  
Richard E. Veilleux ◽  
Gregory M. Peck
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Growth Rates ◽  
Pollen Tube Growth ◽  
Management Strategies ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Load Management ◽  
Crop Load ◽  
Pollen Tube Growth Rate

A greater understanding of apple (Malus ×domestica) pollen tube growth rates can improve crop load management in commercial orchards. Specifically, applications of caustic bloom-thinning chemicals need to occur when enough, but not too many, flowers have been fertilized to achieve crop load densities that balance yields with marketable fruit sizes. In this study, the pollen tube growth rates of five crabapple (Malus sp.) cultivars were measured in the styles of three maternal cultivars at 12, 18, 24, and 30 °C after 24 hours in a growth chamber. Pollen tube growth rates were greatest for ‘Selkirk’ and ‘Thunderchild’ at 12 °C, and greatest for ‘Indian Summer’, ‘Selkirk’, and ‘Thunderchild’ at 24 °C. Pollen tube growth increased with increasing temperatures until 24 °C. There were minimal pollen tube growth rate increases between 24 and 30 °C. Overall, ‘Snowdrift’ had the slowest pollen tube growth rate of the five evaluated crabapple genotypes. At 24 and 30 °C, ‘Indian Summer’ and ‘Thunderchild’ pollen tubes reached the base of the style most frequently, and ‘Snowdrift’ pollen tubes the least frequently. Pollen tube growth rate was also influenced by the maternal cultivar, with Golden Delicious having relatively faster pollen tube growth than Fuji at 24 and 30 °C. Interactions among paternal and maternal genotypes as well as temperature after pollination reveal complex biological and environmental relationships that can be used to develop more precise crop load management strategies for apple orchards.

scholarly journals Pollen-tube growth rate and seed-siring success amongBetula pendulaclones

1999 ◽  
Vol 143 (2) ◽  
pp. 243-251 ◽  
Author(s):  
H. L. PASONEN ◽  
P. PULKKINEN ◽  
M. KÄPYLÄ ◽  
A. BLOM
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tube Growth ◽  
Pollen Tube Growth Rate ◽  
Siring Success

scholarly journals For things to stay the same, things must change: polyploidy and pollen tube growth rates

2020 ◽  
Vol 125 (6) ◽  
pp. 925-935 ◽  
Author(s):  
Joseph H Williams ◽  
Paulo E Oliveira
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Tube Growth ◽  
Volumetric Growth ◽  
Dna Amount ◽  
Cross Sectional ◽  
Wall Area ◽  
Genome Reorganization ◽  
Pollen Tube Growth Rate

Abstract Background and Aims Pollen tube growth rate (PTGR) is an important single-cell performance trait that may evolve rapidly under haploid selection. Angiosperms have experienced repeated cycles of polyploidy (whole genome duplication), and polyploidy has cell-level phenotypic consequences arising from increased bulk DNA amount and numbers of genes and their interactions. We sought to understand potential effects of polyploidy on several underlying determinants of PTGR – pollen tube dimensions and construction rates – by comparing diploid–polyploid near-relatives in Betula (Betulaceae) and Handroanthus (Bignoniaceae). Methods We performed intraspecific, outcrossed hand-pollinations on pairs of flowers. In one flower, PTGR was calculated from the longest pollen tube per time of tube elongation. In the other, styles were embedded in glycol methacrylate, serial-sectioned in transverse orientation, stained and viewed at 1000× to measure tube wall thicknesses (W) and circumferences (C). Volumetric growth rate (VGR) and wall production rate (WPR) were then calculated for each tube by multiplying cross-sectional tube area (πr2) or wall area (W × C), by the mean PTGR of each maternal replicate respectively. Key Results In Betula and Handroanthus, the hexaploid species had significantly wider pollen tubes (13 and 25 %, respectively) and significantly higher WPRs (22 and 18 %, respectively) than their diploid congeners. PTGRs were not significantly different in both pairs, even though wider polyploid tubes were predicted to decrease PTGRs by 16 and 20 %, respectively. Conclusions The larger tube sizes of polyploids imposed a substantial materials cost on PTGR, but polyploids also exhibited higher VGRs and WPRs, probably reflecting the evolution of increased metabolic activity. Recurrent cycles of polyploidy followed by genome reorganization may have been important for the evolution of fast PTGRs in angiosperms, involving a complex interplay between correlated changes in ploidy level, genome size, cell size and pollen tube energetics.

scholarly journals How does genome size affect the evolution of pollen tube growth rate, a haploid performance trait?

2018 ◽  
Author(s):  
John B. Reese ◽  
Joseph H. Williams
Keyword(s):  
Pollen Tube ◽  
Genome Size ◽  
Dna Content ◽  
Pollen Tube Growth ◽  
Gene Dosage ◽  
Tube Growth ◽  
Pollen Competition ◽  
Pollen Tube Growth Rate ◽  
Tube Cell ◽  
Model Weight

ABSTRACTPremise of the StudyMale gametophytes of most seed plants deliver sperm to eggs via a pollen tube. Pollen tube growth rates (PTGRs) of angiosperms are exceptionally rapid, a pattern attributed to more effective haploid selection under stronger pollen competition. Paradoxically, whole genome duplication (WGD) has been common in angiosperms but rare in gymnosperms. Pollen tube polyploidy should initially accelerate PTGR because increased heterozygosity and gene dosage should increase metabolic rates, however polyploidy should also independently increase tube cell size, causing more work which should decelerate growth. We asked how genome size changes have affected the evolution of seed plant PTGRs.MethodsWe assembled a phylogenetic tree of 451 species with known PTGRs. We then used comparative phylogenetic methods to detect effects of neo-polyploidy (within-genus origins), DNA content, and WGD history on PTGR, and correlated evolution of PTGR and DNA content.Key ResultsGymnosperms had significantly higher DNA content and slower PTGR optima than angiosperms, and their PTGR and DNA content were negatively correlated. For angiosperms, 89% of model weight favored Ornstein-Uhlenbeck models with a faster PTGR optimum for neo-polyploids, but PTGR and DNA content were not correlated. In comparisons of within-genus and intraspecific-cytotype pairs, PTGRs of neo-polyploids ≤ paleo-polyploids.ConclusionsGenome size increases should negatively affect PTGR when genetic consequences of WGDs are minimized, as found in intra-specific autopolyploids (low heterosis) and gymnosperms (few WGDs). But in angiosperms, the higher PTGR optimum of neo-polyploids and non-negative PTGR-DNA content correlation suggest that recurrent WGDs have caused substantial PTGR evolution in a non-haploid state.

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