Cell Wall Composition and Structure Define the Developmental Fate of Embryogenic Microspores in Brassica napus

Abstract

Microspore cultures generate a heterogeneous population of embryogenic structures that can be grouped into highly embryogenic structures [exine-enclosed (EE) and loose bicellular structures (LBS)] and barely embryogenic structures [compact callus (CC) and loose callus (LC) structures]. Little is known about the factors behind these different responses. In this study we performed a comparative analysis of the composition and architecture of the cell walls of each structure by confocal and quantitative electron microscopy. Each structure presented specific cell wall characteristics that defined their developmental fate. EE and LBS structures, which are responsible for most of the viable embryos, showed a specific profile with thin walls rich in arabinogalactan proteins (AGPs), highly and low methyl-esterified pectin and callose, and a callose-rich subintinal layer not necessarily thick, but with a remarkably high callose concentration. The different profiles of EE and LBS walls support the development as suspensorless and suspensor-bearing embryos, respectively. Conversely, less viable embryogenic structures (LC) presented the thickest walls and the lowest values for almost all of the studied cell wall components. These cell wall properties would be the less favorable for cell proliferation and embryo progression. High levels of highly methyl-esterified pectin are necessary for wall flexibility and growth of highly embryogenic structures. AGPs seem to play a role in cell wall stiffness, possibly due to their putative role as calcium capacitors, explaining the positive relationship between embryogenic potential and calcium levels.

The Highly Embryogenic Brassica napus DH4079 Line Is Recalcitrant to Agrobacterium-Mediated Genetic Transformation

“…Possible explanations could be the use of DH4079 plant material that was somehow different, or the residual presence of A. tumefaciens in the plant material used to analyze the efficiency of transformation. To avoid these potential problems, we are confident in using the highly embryogenic B. napus DH4079 line, since we routinely perform microspore cultures with microspores isolated from plants of this line [ 35 ] and confirm their high embryogenic response. Moreover, plant samples for PCR were excised from leaves of regenerated plants at the 2–3 true leaf stage upon plant acclimation, avoiding possible Agrobacterium dragging within the sample.…”

The improvement of meat nutrient composition in broiler chickens fed diets containing rice bran tempeh supplemented with cellulose

“…The addition of cellulase did not significantly reduce fat deposition in the abdomen, neck, heart, gizzard, sartorial and total fat deposition. Pectin, cellulose, and ferulic acid, which make up cell wall, are released through hydrolysis (Holland et al, 2020;Jamet and Dunand, 2020;Camacho-Fernández et al, 2021). The potential of cellulose (Cui et al, 2022) and pectin (Sagedhy et al (2015) to reduce abdominal fat is widely known.…”

“…Mandey et al (2016) reported that cellulase reduces blood cholesterol concentration. Cellulase releases pectin, hemicellulose, cellulose, lignin, ferulic acid, minerals, and proteins that make up the cell wall through hydrolysis (Holland et al, 2020;Jamet and Dunand, 2020;Camacho-Fernández et al, 2021). Ferulic acid (de Melo et al, 2017), cellulose (Menge et al,1974) and pectin (Terpstra et al, 1998) reduce the concentration of total cholesterol in the blood.…”

“…The mechanism for reducing fat content of meat by cellulase is unkown. The cell wall encompasses an organized network of cellulose microfibrils integrated within a hydrated geltype matrix typically consisting of pectin, hemi-celluloses, and small amounts of glycoproteins, phenolic acids, minerals and, in some specialized cell-types, lignin (Holland et al, 2020;Jamet and Dunand, 2020;Camacho-Fernández et al, 2021). Cellulase hydrolyzes the cell wall so that the compounds that compose it are hydrolyzed into simpler components.…”

“…Cellulase reduces levels of crude fiber, such as cellulose in feed ingredients (Rohman et al, 2015). Cellulases are able to hydrolyze cell walls (Holland et al, 2020;Jamet and Dunand, 2020;Camacho-Fernández et al, 2021). ), so that cell walls components such as pectin and ferulic acid are released from cell wall complex compounds.…”