Identification of a stem length regulator in sorghum

Identification of a stem length regulator in sorghum

Sorghum Dw2 encodes a protein kinase regulator of stem internode length, a key factor in biomass yield.

The Science

Stem length is a key trait for various sorghum genotypes, impacting biomass yield, plant architecture, and other important crop features. In this study, we identified the gene encoded by Dw2, a locus known to affect stem internode length; this gene encodes a protein kinase homologous to a member of the AGC protein kinase family in the plant Arabidopsis.

The Impact

In energy sorghum, 83% of the shoot biomass accumulates in the stem. Increasing our knowledge of stem growth could help us to improve sorghum hybrids for bioenergy production.


Sorghum is an important C4 grass crop grown for grain, forage, sugar, and bioenergy production. While tall, late flowering landraces are commonly grown in Africa, short early flowering varieties were selected in US grain sorghum breeding programs to reduce lodging and to facilitate machine harvesting. Four loci have been identified that affect stem length (Dw1-Dw4). Subsequent research showed that Dw3 encodes an ABCB1 auxin transporter and Dw1 encodes a highly conserved protein involved in the regulation of cell proliferation. In this study, Dw2 was identified by fine-mapping and further confirmed by sequencing the Dw2 alleles in Dwarf Yellow Milo and Double Dwarf Yellow Milo, the progenitor genotypes where the recessive allele of dw2 originated. The Dw2 locus was determined to correspond to Sobic.006G067700, a gene that encodes a protein kinase that is homologous to KIPK, a member of the AGCVIII subgroup of the AGC protein kinase family in Arabidopsis. In addition to its historical significance, a better understanding of Dw2 function may enable the design of improved sorghum crops.

Contacts (BER PM)

N. Kent Peters
Program Manager, Office of Biological and Environmental Research, 301-903-5549

(PI Contact)

John Mullet
Texas A&M University


This research was funded in part by the DOE Great Lakes Bioenergy Research Center (DOE office of Science BER DE-FC02-07ER64494) and the Perry Adkisson Chair in Agricultural Biology.


Hilley, J.L. et al. Sorghum Dw2 encodes a protein kinase regulator of stem internode length. Scientific Reports 7, 4616 (2017) [DOI:10.1038/s41598-017-04609-5]. 

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