**47. Vestitonereductase and chalconereductase**

The complete mRNA sequences of two soybean genes-vestitone reductase and chalcone re‐ ductase, were amplified using the rapid amplification of cDNA ends methods. Soybean ves‐ titone reductase gene encodes a 327 amino-acid protein with pronounced resemblance to *Medicago sativa* vestitone reductase. The soybean chalcone reductase gene encodes a 314 ami‐ no-acid protein highly homologous to the kudzu vine and medicago sativa chalcone reduc‐ tases. The two genes were differentially expressed in soybean embryos and endosperm, flowers, leaves, stems, and roots [51].

## **48. Genes related to 2-oxoglutarate-dependentdioxygenases**

A screening for genes involved in root nodule senescence has resulted in the isolation of the senescence-associated nodulin 1 (SAN1) multigene family from soybean. The SAN1-encod‐ ed proteins display sequence resemblance and highly conserved motifs with plant 2-oxoglu‐ tarate-dependent dioxygenases (2-ODDs). SAN1A is downregulated whereas SAN1B is upregulated during senescence induced by treatment with fixed nitrogen or darkness. The expression of the SAN1genes is not found only in nodules, signifying a more general role in plant metabolism [52].

## **49. 5'-adenylylsulfate reductase**

Soybean seeds contain only low levels of sulfur-containing amino acids. Although expressed in various tissues throughout the plant, there is an abundant expression of the APS reduc‐ tase gene and activity of the encoded protein in the early developmental stages of soybean seed, which decreases as the seed matures. Sulfur and phosphorus deprivation and coldtreatment elevate the expression level, while nitrogen starvation reduces APS reductase mRNA transcript and protein levels. This study allows an insight into the sulfur assimila‐ tion pathway [53].
