Immunolocalization of pectic polysaccharides during abscission in pea seeds (Pisum sativum L.) and in abscission less def pea mutant seeds

Abstract

BackgroundIn pea seeds (Pisum sativum L.), the presence of the Def locus determines abscission event between its funicle and the seed coat. Cell wall remodeling is a necessary condition for abscission of pea seed. The changes in cell wall components in wild type (WT) pea seed with Def loci showing seed abscission and in abscission less def mutant peas were studied to identify the factors determining abscission and non-abscission event.MethodsChanges in pectic polysaccharides components were investigated in WT and def mutant pea seeds using immunolabeling techniques. Pectic monoclonal antibodies (1 → 4)-β-d-galactan (LM5), (1 → 5)-α-l-arabinan(LM6), partially de-methyl esterified homogalacturonan (HG) (JIM5) and methyl esterified HG (JIM7) were used for this study.ResultsPrior to abscission zone (AZ) development, galactan and arabinan reduced in the predestined AZ of the pea seed and disappeared during the abscission process. The AZ cells had partially de-methyl esterified HG while other areas had highly methyl esterified HG. A strong JIM5 labeling in the def mutant may be related to cell wall rigidity in the mature def mutants. In addition, the appearance of pectic epitopes in two F3 populations resulting from cross between WT and def mutant parents was studied. As a result, we identified that homozygous dominant lines (Def/Def) showing abscission and homozygous recessive lines (def/def) showing non-abscission had similar immunolabeling pattern to their parents. However, the heterogeneous lines (Def/def) showed various immunolabeling pattern and the segregation pattern of the Def locus.ConclusionsThrough the study of the complexity and variability of pectins in plant cell walls as well as understanding the segregation patterns of the Def locus using immunolabeling techniques, we conclude that cell wall remodeling occurs in the abscission process and de-methyl esterification may play a role in the non-abscission event in def mutant. Overall, this study contributes new insights into understanding the structural and architectural organization of the cell walls during abscission.

Mapping Pectic-Polysaccharide Epitopes in Cell Walls of Forage Chicory (Cichorium intybus) Leaves

“…Other studies have shown that the LM5 epitope was also completely absent in walls newly formed from mesophyll-derived protoplasts of sugar beet ( Majewska-Sawka and Münster, 2003 ). The within cell wall distribution of arabinans compared with galactans found in the present study is consistent with the results of studies on tomato ( Solanum lycopersicum ) fruit ( Jones et al, 1997 ; Wang et al, 2019 ), potato ( Solanum tuberosum ) tuber tissue ( Buffetto et al, 2015 ), pea ( Pisum sativum ) seeds ( Lee et al, 2016 ), and flax ( Linum usitatissimum ; Vicré et al, 1998 ). These studies found that the (1→4)-β-galactan was restricted to a thin layer close to the plasma membrane.…”

Dynamic Changes of Pectin Epitopes in Cell Walls during the Development of the Procambium–Cambium Continuum in Poplar

“…This also indicated that, although the procambium and cambium were a continuum of the same vascular meristem, the characteristics of their cell walls were different. In the primary growth system, such as the root apex of carrot, flax and Arabidopsis, the galactan epitope was observed to appear at certain points during cell differentiation, while the arabinan epitope was most abundant in meristematic cells [ 44 , 45 , 46 , 47 , 48 ].…”

Intact funiculus in mature harvested seeds of field pea (Pisum sativum L.): preliminary investigation and possible implications

“…Lee et al. (2016) compared the structural and architectural organization of the abscission processes of normal and intact funiculus. Recently, Chan et al.…”