Full-length cDNA sequences of two exo-beta-glucanases, LP-ExoI and LP-ExoII, secreted into cell walls of lily (Lilium longiflorum) pollen tube, were determined by RT-PCR. LP-ExoI exhibited over 80% similarity to LP-ExoII at both DNA and amino acid levels. RT-PCR showed that LP-ExoI transcripts were abundant in pollen grains and tubes, but could not be detected in leaf, stem, stigma, style, ovary, petal, filament, young root, young bud, and scale leaf of bulb. However, LP-ExoII transcripts ubiquitously existed in all the tissues tested. To determine the potential substrates of exo-beta-glucanases, cell wall components of lily tissues were analyzed. Linkage analysis revealed that pollen tubes contained high levels of 3-Glc in hemicellulose (44.3%), while pollen grains had no detectable 3-Glc. The hemicellulose fraction of pollen tubes was treated with lichenase and the product was analyzed by HPLC-PAD to determine the origin of 3-Glc. Specific tetra-saccharide was liberated from hemicellulose of pollen tubes, suggesting the presence of 1,3 : 1,4-beta-glucan in lily pollen tube hemicellulose. The structure of this 1,3 : 1,4-beta-glucan may be different from cereal plant 1,3 : 1,4-beta-glucan, since tri-saccharide was not detected in hemicellulose fraction after lichenase treatment. LP-ExoI and LP-ExoII, expressed in pollen grains and tubes, may be involved in the regulation of pollen tube elongation by hydrolyzing callose and 1,3 : 1,4-beta-glucan within pollen tube walls.
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http://dx.doi.org/10.1093/pcp/pch049 | DOI Listing |
Plant Physiol
December 2024
Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 00 Prague 6, Czech Republic.
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View Article and Find Full Text PDFPlant Cell Environ
January 2025
Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China.
Floral organ development, pollen germination and pollen tube growth are crucial for plant sexual reproduction. Phytohormones maintain these processes by regulating the expression and activity of various transcription factors. ICE1, a MYC-like bHLH transcription factor, has been revealed to be involved in cold acclimatisation of Arabidopsis.
View Article and Find Full Text PDFPlant Biol (Stuttg)
January 2025
Laboratório de Ecologia Vegetal, Departamento de Biologia Geral, Universidade Estadual de Montes Claros, Montes Claros, Minas Gerais, Brazil.
The success of pollen-pistil interaction in Mauritia flexuosa (buriti), a palm adapted to the humid ecosystems, 'veredas', within the Cerrado, is influenced by intrinsic and environmental factors. Its supra-annual flowering, dioecy, and adverse climate conditions pose challenges for fertilization, therefore information on floral biology is essential. This study aimed to ascertain stigma receptivity, and elucidate structural, cytochemical, and ultrastructural aspects of the pollen-pistil relationship.
View Article and Find Full Text PDFJ Integr Plant Biol
January 2025
School of Advanced Agricultural Sciences, Peking University, Beijing, 100871, China.
Heat stress (HS) at the reproductive stage detrimentally affects crop yields and seed quality. However, the molecular mechanisms that protect reproductive processes in plants under HS remain largely unknown. Here, we report that Acetylation Lowers Binding Affinity 3 (ALBA3) is crucial for safeguarding male fertility against HS in Arabidopsis.
View Article and Find Full Text PDFPlant Mol Biol
January 2025
Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, 382355, India.
Ensuring species integrity and successful reproduction is pivotal for the survival of angiosperms. Members of Brassicaceae family employ a "lock and key" mechanism involving stigmatic (sRALFs) and pollen RALFs (pRALFs) binding to FERONIA, a Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) receptor, to establish a prezygotic hybridization barrier. In the absence of compatible pRALFs, sRALFs bind to FERONIA, inducing a lock state for pollen tube penetration.
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