The endexine: a frequently overlooked pollen wall layer and a simple method for detection

Weber, Martina; Ulrich, Silvia

doi:10.1080/00173131003743949

Cited by 32 publications

(22 citation statements)

References 27 publications

(36 reference statements)

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“…Sexine is mainly made up of sporopollenin, which is composed of complex biopolymers such as long-chain fatty acids or long aliphatic chains (Scott, 1994). However, the nexine layer, a conserved element of the pollen wall, is frequently overlooked and the knowledge regarding this layer is rather meager (Weber and Ulrich, 2010). In the tek mutant, sporopollenin is synthesized normally while the nexine layer is completely absent (Lou et al, 2014), suggesting that sporopollenin is not essential for nexine formation.…”

Section: Discussion Agps Appear To Be the Major Components Of The Nexmentioning

confidence: 98%

Arabidopsis AT-hook Protein TEK Positively Regulates the Expression of Arabinogalactan Proteins for Nexine Formation

Jia

Zhu

et al. 2015

Molecular Plant

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Nexine is a conserved layer of the pollen wall. We previously reported that the nexine layer is absent in the knockout mutant of Arabidopsis TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK) gene. In this study, we investigated the molecular regulatory functions of TEK in pollen development and identified the genes encoding Arabinogalactan proteins (AGPs) as direct targets of TEK, which are essential for nexine formation. Phenotypic similarity between tek and the TEK-SRDX transgenic lines suggest that TEK plays a role in transcriptional activation in anther development. Microarray analysis identified a total of 661 genes downregulated in tek, including four genes encoding AGPs, AGP6, AGP11, AGP23, and AGP40. Electrophoretic mobility shift assays showed that TEK could directly bind the nuclear matrix attachment region (MAR) and the promoter of AGP6. Chromatin immunoprecipitation followed by PCR analysis demonstrated that TEK is enriched in the promoters of the four AGP genes. Expression of AGP6 driven by the TEK promoter in tek partially rescued both nexine formation and plant fertility. These results indicate that TEK directly regulates AGP expression in the anther to control nexine layer formation. We also proposed that glycoproteins might be essential components of the nexine layer in the pollen wall.

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Section: Discussion Agps Appear To Be the Major Components Of The Nexmentioning

confidence: 98%

Arabidopsis AT-hook Protein TEK Positively Regulates the Expression of Arabinogalactan Proteins for Nexine Formation

Jia

Zhu

et al. 2015

Molecular Plant

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“…While little is known of the detailed composition of nexine, suberin and sporopollenin (comprising both nexine and sexine) each contain polymerized fatty acids and aromatic compounds (Ariizumi and Toriyama, 2011;Beisson et al, 2012;Nawrath et al, 2013). Moreover, lily (Lilium longiflorum) nexine is first synthesized as lamellae, and in some plant species mature nexine is lamellar (Dickinson and Heslop-Harrison, 1968;Weber and Ulrich, 2010). Thus, nexine may have a similar structure to suberin.…”

Section: Discussion Abcg Transporters Are Required For Barrier Synthesismentioning

confidence: 99%

ABCG Transporters Are Required for Suberin and Pollen Wall Extracellular Barriers inArabidopsis

et al. 2014

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Effective regulation of water balance in plants requires localized extracellular barriers that control water and solute movement. We describe a clade of five Arabidopsis thaliana ABCG half-transporters that are required for synthesis of an effective suberin barrier in roots and seed coats (ABCG2, ABCG6, and ABCG20) and for synthesis of an intact pollen wall (ABCG1 and ABCG16). Seed coats of abcg2 abcg6 abcg20 triple mutant plants had increased permeability to tetrazolium red and decreased suberin content. The root system of triple mutant plants was more permeable to water and salts in a zone complementary to that affected by the Casparian strip. Suberin of mutant roots and seed coats had distorted lamellar structure and reduced proportions of aliphatic components. Root wax from the mutant was deficient in alkylhydroxycinnamate esters. These mutant plants also had few lateral roots and precocious secondary growth in primary roots. abcg1 abcg16 double mutants defective in the other two members of the clade had pollen with defects in the nexine layer of the tapetum-derived exine pollen wall and in the pollen-derived intine layer. Mutant pollen collapsed at the time of anther desiccation. These mutants reveal transport requirements for barrier synthesis as well as physiological and developmental consequences of barrier deficiency.

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“…To confirm our opinion, we made an acetolysis test with mature pollen grains of Magnolia sieboldii (see Figure 13C), and used a simple method to detect the endexine by staining with potassium permanganate (Weber & Ulrich, 2010). With glutar-osmium fixation and conventional staining with uranyl acetate and lead citrate, we got pronounced contrast of the granular layer ( Figure 12B-H).…”

Section: Intine 'Under Question'mentioning

confidence: 99%

Sporoderm development and substructure inMagnolia sieboldiiand other Magnoliaceae: an interpretation

Gabarayeva

Grigorjeva

2012

Grana

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The endexine: a frequently overlooked pollen wall layer and a simple method for detection

Cited by 32 publications

References 27 publications

Arabidopsis AT-hook Protein TEK Positively Regulates the Expression of Arabinogalactan Proteins for Nexine Formation

Arabidopsis AT-hook Protein TEK Positively Regulates the Expression of Arabinogalactan Proteins for Nexine Formation

ABCG Transporters Are Required for Suberin and Pollen Wall Extracellular Barriers inArabidopsis

Sporoderm development and substructure inMagnolia sieboldiiand other Magnoliaceae: an interpretation

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