** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE PRODUCTIVITY OF A PLANT IS DETERMINED BY ITS CAPACITY TO CAPTURE LIGHT AND CONVERT ITINTO BIOMASS OVER THE COURSE OF THE GROWING SEASON. CANOPY ARCHITECTURE HAS A SIGNIFICANT IMPACT ON LIGHT INTERCEPTION, PHOTOSYNTHETIC EFFICIENCY, PLANTING DENSITY AND ULTIMATELY PLANT PRODUCTIVITY. AS SUCH, OPTIMIZATION OF IT HAS BEEN A VITAL GOAL IN PLANT BREEDING. IN CEREAL CROPS SUCH AS MAIZE SORGHUM, RICE, AND WHEAT, CANOPY STRUCTURE IS LARGELY DETERMINED BY LEAF ANGLE - THE INCLINATION BETWEEN THE LEAF BLADE MIDRIB AND THE VERTICAL STEM, AND UPRIGHT PLANT ARCHITECTURE WITH ERECT LEAVES HAS BEEN IDENTIFIED TO BE A KEY COMPONENT IN THE DEVELOPMENT OF HIGH-YIELDING CULTIVARS.IN LEGUME SPECIES SUCH AS SOYBEAN, COMMON BEAN, AND PEA, CANOPY ARCHITECTURE IS MAINLY DETERMINED BY BRANCH ANGLE AND LEAFLET SHAPE. IN THE PAST FEW DECADES, A NUMBER OF MAJOR QUANTITATIVE TRAIT LOCI (QTLS) CONTROLLING LEAF ANGLES IN MAIZE AND RICE HAVE BEEN IDENTIFIED, CLONED, AND USED TO OPTIMIZE PLANT ARCHITECTURE FOR ENHANCEMENT OF GRAINYIELDS. BY CONTRAST, LITTLE IS KNOWN REGARDING HOW BRANCH ANGLE AND LEAFLET SHAPE IN LEGUMES ARE CONTROLLED AND REGULATED AT THE MOLECULAR LEVEL. THROUGH A DECADE OF EFFORTS, THE PD AND COLLABORATORS HAVE DEVELOPED TWO LARGE RECOMBINANT INBRED LINE (RIL) POPULATIONS COMPOSED OF >3,000 INDIVIDUAL LINES DERIVED FROM TWO CROSSES BETWEEN A SOYBEAN CULTIVAR WILLIAMS 82 AND EACH OF TWO WILD SOYBEAN ACCESSIONS, ONE OF WHICH CARRIES TWO QTLS CONFERRING TOLERANCE TO SOYBEAN CYST NEMATODE.THESE RILS HAVE BEEN DEMONSTRATED TO BE VERY POWERFUL FOR GENETIC DISSECTION OF COMPLEX DOMESTICATION-RELATED TRAITS.MANY OF WHICH HAVE POTENTIAL AS TARGETS FOR FURTHER SELECTION IN MODERN BREEDING PROGRAMS. SOME OF THE RILS HAD BEEN SELECTED AND CROSSED WITH ELITE SOYBEAN VARIETIES FOR FURTHER DISSECTION OF COMPLEX TRAITS OF AGRONOMIC IMPORTANCE OR FOR GERMPLASM ENHANCEMENT. USING THESES RESOURCES, THE PD AND CO-WORKERS HAVE RECENTLY FINE-MAPPED A MAJOR QTL - QGMBA1 - MODULATING BRANCH ANGLE INTO A GENOMIC REGION ON CHROMOSOME 19, WHICH ONLY HARBORS A SINGLE PUTATIVE LONG NON-CODING RNA (LNCRNA) GENE GLYMA.19G016200. IN ADDITION, THE TEAM HAVE FINE-MAPPED TWO MAJOR QTLS - QLSH1 AND QLSH2 - WITH EPISTATIC EFFECTS IN REGULATING LEAFLET SHAPE INTO A GENOMIC REGION ON CHROMOSOME 16 AND A GENOMIC REGION ON CHROMOSOME 6, RESPECTIVELY. THE FORMER CONTAINS THREE LNCRNA GENES, OF WHICH, GLYMA.16G012300 IS EXPRESSED IN LEAFLETS AND THE OTHER TWO LNCRNA-LIKE GENES ARE NOT EXPRESSED IN DEVELOPING LEAFLETS, WHEREAS THE LATTER ONLY CONTAINS A SINGLE GENE GLYMA06G205800, WHICH IS PREDICTED TO ENCODE A MADS-BOX TRANSCRIPTION FACTOR GENE.THE CENTRAL GOAL OF THIS PROJECT IS TO ELUCIDATE THE MOLECULAR MECHANISMS REGULATING THESE TWO TRAITS ASSOCIATED WITH CANOPY ARCHITECTURE IN SOYBEANUSINGA COMBINATION OF GENETICS, GENOMICS, TRANSCRIPTOMICS, MOLECULAR BIOLOGY, AND BIOCHEMICAL APPROACHES. WE ANTICIPATE THAT THE PROPOSED WORK WILL PROVIDE NOVEL INSIGHTS INTO THE MECHANISMS MODULATING BRANCH ANGLE AND LEAFLET SHAPE, EXEMPLIFY THE BIOLOGICAL SIGNIFICANCE OF LNCRNAS, PAVE THE WAY FOR OPTIMIZING CANOPY ARCHITECTURE TOWARD ENHANCED YIELD POTENTIAL IN SOYBEAN, AND FACILITATE EXPLOITATION OF WILD SOYBEAN GERMPLASM FOR SUSTAINABLE IMPROVEMENT OF SOYBEAN CULTIVARS.
$650,000FY2022National Institute of Food and AgricultureUSDA
Purdue University, West Lafayette IN