Pectin secretion and distribution in the anther during pollen development in Lilium

Aouali, Nasséra; Laporte, Philippe; Clément, Christophe

doi:10.1007/s004250000469

Cited by 63 publications

(50 citation statements)

References 32 publications

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“…In many species, such as tobacco (Li et al, 1995), Arabidopsis (Van Aelst and Van Went, 1992; Rhee and Somerville, 1998), Lilium hybrida (Aouali et al, 2001), Euphorbia peplus (Suárez-Cervera et al, 2002), Zygophyllum fabago (Castells et al, 2003), and Larix decidua (Rafinska et al, 2014), the intine of mature pollen grains is mostly composed of weakly methylesterified HG or a mix of highly and weakly methylesterified HGs, the latter being more abundant. The almost absent labeling of weakly methylesterified HG with John Innes Monoclonal5 at the pollen mother cell and tetrad stages (Rhee and Somerville, 1998) but its strong detection in the intine at the late microspore stage and mature dry Arabidopsis pollen grains (Van Aelst and Van Went, 1992; Rhee and Somerville, 1998) indicate an early action of PMEs during pollen formation and maturation.…”

Section: Discussionmentioning

confidence: 99%

PECTIN METHYLESTERASE48 Is Involved in Arabidopsis Pollen Grain Germination

et al. 2014

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Germination of pollen grains is a crucial step in plant reproduction. However, the molecular mechanisms involved remain unclear. We investigated the role of PECTIN METHYLESTERASE48 (PME48), an enzyme implicated in the remodeling of pectins in Arabidopsis (Arabidopsis thaliana) pollen. A combination of functional genomics, gene expression, in vivo and in vitro pollen germination, immunolabeling, and biochemical analyses was used on wild-type and Atpme48 mutant plants. We showed that AtPME48 is specifically expressed in the male gametophyte and is the second most expressed PME in dry and imbibed pollen grains. Pollen grains from homozygous mutant lines displayed a significant delay in imbibition and germination in vitro and in vivo. Moreover, numerous pollen grains showed two tips emerging instead of one in the wild type. Immunolabeling and Fourier transform infrared analyses showed that the degree of methylesterification of the homogalacturonan was higher in pme482/2 pollen grains. In contrast, the PME activity was lower in pme482/2, partly due to a reduction of PME48 activity revealed by zymogram. Interestingly, the wild-type phenotype was restored in pme482/2 with the optimum germination medium supplemented with 2.5 mM calcium chloride, suggesting that in the wild-type pollen, the weakly methylesterified homogalacturonan is a source of Ca 2+ necessary for pollen germination. Although pollen-specific PMEs are traditionally associated with pollen tube elongation, this study provides strong evidence that PME48 impacts the mechanical properties of the intine wall during maturation of the pollen grain, which, in turn, influences pollen grain germination.

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Section: Discussionmentioning

confidence: 99%

PECTIN METHYLESTERASE48 Is Involved in Arabidopsis Pollen Grain Germination

et al. 2014

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“…Not all carbohydrates are nutritionally useful, e.g. pectin is an important structural component of the cell wall and essential in plant growth and development but has no known nutritional value for bees (Aouali et al, 2001 andDe Halac et al, 2003). Pectin content in A. greatheadii var.…”

Section: Mean (±Sd) Mean (±Sd)mentioning

confidence: 99%

Nutritional content of fresh, bee-collected and stored pollen of Aloe greatheadii var. davyana (Asphodelaceae)

2006

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Aloe greatheadii var. davyana is the most important indigenous South African bee plant. Fresh, bee-collected and stored pollen of this aloe was collected and analysed for its nutritional content, including amino acid and fatty acid composition. Highly significant differences were found between the three types of pollen. Collection and storage by the bees resulted in increased water (13-21% wet weight) and carbohydrate content (35-61% dry weight), with a resultant decrease in crude protein (51-28% dry weight) and lipid content (10-8% dry weight). Essential amino acids were present in equal or higher amounts than the required minimum levels for honeybee development, with the exception of tryptophan. Fatty acids comprised a higher proportion of total lipid in fresh pollen than in bee-collected and stored pollen. This study is the first to compare the changes that occur in pollen of a single species after collection by honeybees. Graphical abstractThe first study to characterise changes in pollen of a single species after collection by honeybees reports highly significant differences. The addition of nectar to fresh pollen results in increased water and carbohydrate content, and decrease in crude protein and lipid content. Article Outline

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“…3A). Pectin constitutes a major component of plant cell walls, and pectic polysaccharides are involved in the formation of different layers in pollen walls (41). They are particularly prominent in pollen tubes, where they control cell outgrowth during maturation (42).…”

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confidence: 99%

Functional diversity within the simple gut microbiota of the honey bee

Engel

Martinson

Moran

2012

Proc. Natl. Acad. Sci. U.S.A.

727

775

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Animals living in social communities typically harbor a characteristic gut microbiota important for nutrition and pathogen defense. Accordingly, in the gut of the honey bee, Apis mellifera , a distinctive microbial community, composed of a taxonomically restricted set of species specific to social bees, has been identified. Despite the ecological and economical importance of honey bees and the increasing concern about population declines, the role of their gut symbionts for colony health and nutrition is unknown. Here, we sequenced the metagenome of the gut microbiota of honey bees. Unexpectedly, we found a remarkable degree of genetic diversity within the few bacterial species colonizing the bee gut. Comparative analysis of gene contents suggests that different species harbor distinct functional capabilities linked to host interaction, biofilm formation, and carbohydrate breakdown. Whereas the former two functions could be critical for pathogen defense and immunity, the latter one might assist nutrient utilization. In a γ-proteobacterial species, we identified genes encoding pectin-degrading enzymes likely involved in the breakdown of pollen walls. Experimental investigation showed that this activity is restricted to a subset of strains of this species providing evidence for niche specialization. Long-standing association of these gut symbionts with their hosts, favored by the eusocial lifestyle of honey bees, might have promoted the genetic and functional diversification of these bee-specific bacteria. Besides revealing insights into mutualistic functions governed by the microbiota of this important pollinator, our findings indicate that the honey bee can serve as a model for understanding more complex gut-associated microbial communities.

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Pectin secretion and distribution in the anther during pollen development in Lilium

Cited by 63 publications

References 32 publications

PECTIN METHYLESTERASE48 Is Involved in Arabidopsis Pollen Grain Germination

PECTIN METHYLESTERASE48 Is Involved in Arabidopsis Pollen Grain Germination

Nutritional content of fresh, bee-collected and stored pollen of Aloe greatheadii var. davyana (Asphodelaceae)

Functional diversity within the simple gut microbiota of the honey bee

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