Dt2Is a Gain-of-Function MADS-Domain Factor Gene That Specifies Semideterminacy in Soybean  

Abstract

Similar to Arabidopsis thaliana, the wild soybeans (Glycine soja) and many cultivars exhibit indeterminate stem growth specified by the shoot identity gene Dt1, the functional counterpart of Arabidopsis TERMINAL FLOWER1 (TFL1). Mutations in TFL1 and Dt1 both result in the shoot apical meristem (SAM) switching from vegetative to reproductive state to initiate terminal flowering and thus produce determinate stems. A second soybean gene (Dt2) regulating stem growth was identified, which, in the presence of Dt1, produces semideterminate plants with terminal racemes similar to those observed in determinate plants. Here, we report positional cloning and characterization of Dt2, a dominant MADS domain factor gene classified into the APETALA1/SQUAMOSA (AP1/SQUA) subfamily that includes floral meristem (FM) identity genes AP1, FUL, and CAL in Arabidopsis. Unlike AP1, whose expression is limited to FMs in which the expression of TFL1 is repressed, Dt2 appears to repress the expression of Dt1 in the SAMs to promote early conversion of the SAMs into reproductive inflorescences. Given that Dt2 is not the gene most closely related to AP1 and that semideterminacy is rarely seen in wild soybeans, Dt2 appears to be a recent gain-of-function mutation, which has modified the genetic pathways determining the stem growth habit in soybean.

Selection for a Zinc-Finger Protein Contributes to Seed Oil Increase during Soybean Domestication

“…This higher expression promotes the thickening of fiber cap cells in cultivated soybean to avoid shattering (Dong et al, 2014). For stem growth habit, Dt1 and Dt2 also may have been subjected to selection by expression during soybean domestication (Tian et al, 2010;Ping et al, 2014).…”

GmHs1-1, encoding a calcineurin-like protein, controls hard-seededness in soybean

“…Genomic DNA isolation, PCR primer design, PCR amplification, SNP-based cleaved amplified polymorphic sequence (CAPS) marker development, PCR fragment purification, total RNA isolation, cDNA synthesis by RT-PCR, qRT-PCR and sequencing of PCR and RT-PCR fragments were conducted as previously described 32,35 . Primers used for PCR, RT-PCR, qRT-PCR and sequencing are listed in Supplementary Table 6.…”

Semi-determinate growth habit adjusts the vegetative-to-reproductive balance and increases productivity and water-use efficiency in tomato ( Solanum lycopersicum )

“…If so, this improved vegetative-to-reproductive balance in tomato maybe not solely the consequence of the mutations studied here or their gene dosage (Jiang et al, 2013), but rather the expression of a more general process for crop productivity. This suggests a way to manipulate other crops which have varieties showing different growth habits but not necessarily controlled by the CETS gene family (George, 1970;Ping et al, 2014). An interesting analogy is the Green Revolution, where the yield of cereal crops, with a completely different growth habit, was improved by converting the overly vegetative tall varieties into well-balanced semi-dwarf ones (Peng et al, 1999;Spielmeyer et al, 2002).…”