Remobilization and fate of sulphur in mustard

Abstract

Background and AimsSulphur (S) is an essential macronutrient involved in numerous metabolic pathways required for plant growth. Crops of the plant family Brassicaceae require more S compared with other crops for optimum growth and yield, with most S ultimately sequestered in the mature seeds as the storage proteins cruciferin and napin, along with the unique S-rich secondary metabolite glucosinolate (GSL). It is well established that S assimilation primarily takes place in the shoots rather than roots, and that sulphate is the major form in which S is transported and stored in plants. We carried out a developmental S audit to establish the net fluxes of S in two lines of Brassica juncea mustard where seed GSL content differed but resulted in no yield penalty.MethodsWe quantified S pools (sulphate, GSL and total S) in different organs at multiple growth stages until maturity, which also allowed us to test the hypothesis that leaf S, accumulated as a primary S sink, becomes remobilized as a secondary source to meet the requirements of GSL as the dominant seed S sink.Key ResultsMaximum plant sulphate accumulation had occurred by floral initiation in both lines, at which time most of the sulphate was found in the leaves, confirming its role as the primary S sink. Up to 52 % of total sulphate accumulated by the low-GSL plants was lost through senesced leaves. In contrast, S from senescing leaves of the high-GSL line was remobilized to other tissues, with GSL accumulating in the seed from commencement of silique filling until maturity.ConclusionWe have established that leaf S compounds that accumulated as primary S sinks at early developmental stages in condiment type B. juncea become remobilized as a secondary S source to meet the demand for GSL as the dominant seed S sink at maturity.

May mineral composition trigger or limit the protein content in soybean (Glycine max (L.) Merrill) seeds? Insights from a survey on 95 varieties cultivated in Brazil

“…Despite playing important roles in a myriad of metabolic processes (Borpatragohain et al, 2019; Q. Li et al, 2020; Narayan et al, 2022), sulphur encompasses both cysteine and methionine sulphur-amino acids residues in the primary structure of the glycinin, one of the most abundant fractions of globulin-like storage proteins in soybean seeds (Derbyshire et al, 1976; C.…”

Genome-Wide Association Reveals Trait Loci for Seed Glucosinolate Accumulation in Indian Mustard (Brassica juncea L.)

“…In total, three biological replicates per accession (consisting of two individual seeds each) were used for quantifying GSL concentrations, following the method by Borpatragohain et al, 2019 [72]. In brief, two seeds per sample were placed in an Eppendorf safe-lock tube, to which 1.5 mL of 70% methanol and a 5 mm stainless-steel bead was added.…”

Leaf senescence and its regulation with phytohormones and essential elements: An overview

“…Directing crop breeding to decrease glucosinolate levels, as well as storage protein, can result in modified target proteins. At this time, the absence of extensive information explaining the intake, circulation and chance of metabolites containing S in crops is preventing this approach [64].…”

“…Despite the abundance of magnesium in the soil, it is frequently deficient in the field due to soil acidity and competition with other cations such as hydrogen (H + ), potassium (K + ), calcium (Ca 2+ ), and ammonium (NH 4+ ) in the soil [86][87][88][89][90], particularly in very sandy soils and in the cultivation of tobacco and potatoes [85][86]. There have been various studies that have identified the signs and symptoms of magnesium shortage in crops [61][62][63][64][65]. Under typical circumstances, the magnesium concentration of the vegetative portions is between 0.15% and 0.35% of the dry weight of the plant [77].…”