The Aberrant Cell Walls of Boron-Deficient Bean Root Nodules Have No Covalently Bound Hydroxyproline-/Proline-Rich Proteins

Abstract

B-deficient bean (Phaseolus vulgaris L.) nodules examined by light microscopy showed dramatic anatomical changes, mainly in the parenchyma region. Western analysis of total nodule extracts examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that one 116-kD polypeptide was recognized by antibodies raised against hydroxyproline-rich glycoproteins (HRGPs) from the soybean (Glycine max) seed coat. A protein with a comparable molecular mass of 116 kD was purified from the cell walls of soybean root nodules. The amino acid composition of this protein is similar to the early nodulin (ENOD2) gene. Immunoprecipitation of the soybean ENOD2 in vitro translation product showed that the soybean seed coat anti-HRGP antibodies recognized this early nodulin. Furthermore, we used these antibodies to localize the ENOD2 homolog in bean nodules. Immunocytochemistry revealed that in B-deficient nodules ENOD2 was absent in the walls of the nodule parenchyma. The absence of ENOD2 in B-deficient nodules was corroborated by performing hydroxyproline assays. Northern analysis showed that ENOD2 mRNA is present in B-deficient nodules; therefore, the accumulation of ENOD2 is not affected by B deficiency, but its assembly into the cell wall is. B-deficient nodules fix much less N2 than control nodules, probably because the nodule parenchyma is no longer an effective O2 barrier.

Dry Matter Partitioning and Mineral Constitution Response of Sunflower (Helianthus annuus) to Integrated Nitrogen and Boron Nutrition in Calcareous Soils

“…Boron is also involved in the formation of pollen tube, seed filling, transportation of sugars, nucleic acid metabolism, lignifications, respiration, protein synthesis, RNA, IAA and carbohydrates metabolism, transportation across the membranes, enzymes, growth regulators and N uptake which finally enhanced the growth of sunflower (Shaaban, 2010). In calcareous soils, there is a problem of nutrient uptake due to low organic matter, high pH and temperature; and B supply in these soils may be helpful to increase nitrogenase enzyme activity by providing adequate oxygen for N uptake (Bonilla et al, 1997). In view of above considerations, the current study was undertaken to explore the interactive effect of N and B nutrition on growth and mineral uptake of sunflower, and also to determine the adequate N and B application rates for higher sunflower productivity in calcareous soils.…”

Role of Boron Nutrient in Nodules Growth and Nitrogen Fixation in Soybean Genotypes Under Water Stress Conditions

“…Boron is required for nodules growth and nitrogen fixation [9,[11][12][13], and boron deficiency can occur under certain environmental stress factors even when boron level in soil is adequate [19], leading to yield loss. Among the environmental stress factors that can lead to boron deficiency in plants is drought or water stress.…”

“…Previous research indicated the involvement of B in cell wall structure [5,6]; cell membrane integrity [2,7]; sugar metabolism [2], especially sugar alcohols [3,8]; nitrogen assimilation and fixation [9,10]; nodules [11,12], nodullin protein (ENOD2) and malfunction of oxygen diffusion barrier [13]; phenolic metabolism [2,14,15]; ion uptake [2,16]; and plasma membrane-bount H+ ATPase [7,17,18].…”

The impact of aluminium on the distribution of cell wall glycoproteins of pea root tip and their Al-binding capacity

“…They commonly assume a polyproline-ll helical conformation, which is associated with the protein rigidity and rod-like structure (Cassab 1998). They have been identified in relation to the pericycle and vascular tissue development in the root apex of pea and other species (Casero et al 1998).Although some advances have been made in the isolation and characterization of the proteins that may play key roles in cell wall expansion and factors influencing this process (Fry 1991;McQueen-Mason et al 1992;Bonilla et al 1997), it remains to be determined how each class of structural proteins can potentially contribute to the rigidity of the whole structure. Immobilization of the structural proteins and reinforcement of existing crosslinking of proteins have been demonstrated in response to developmental regulation (Bolwell 1993).…”

“…Although some advances have been made in the isolation and characterization of the proteins that may play key roles in cell wall expansion and factors influencing this process (Fry 1991;McQueen-Mason et al 1992;Bonilla et al 1997), it remains to be determined how each class of structural proteins can potentially contribute to the rigidity of the whole structure. Immobilization of the structural proteins and reinforcement of existing crosslinking of proteins have been demonstrated in response to developmental regulation (Bolwell 1993).…”