Nutrient and water limitations contribute to yield losses in semi-arid regions. Therefore, crop rotations incorporating nitrogen-fixing legumes and drought-tolerant sorghum varieties offer a strategy to improve the utilization of scarce soil resources. Under semi-arid, field-like conditions, sorghum crop rotations with either cowpea pre-crop or fallow, including two early and three late maturing genotypes, were tested to identify stress adaptation traits of sorghum to water and phosphorus limitations. Morphological and physiological parameters were evaluated on a single-plant basis. Lower soil P content significantly delayed flowering compared to higher P levels. However, improved P availability arising from pre-crop residues reduced this effect. Mycorrhizal infection rates and root-to-shoot ratios were positively correlated with panicle N and P content at anthesis under low P conditions. Although drought significantly impacted yield, early maturing genotypes with the highest reduction in shoot biomass and reduced water use before flowering, could sustain yield production. Early-maturing genotypes characterized by high root-to-shoot ratios, rapid AMF establishment, and reduced water use before flowering exhibit a strong potential for maintaining yield and biomass production on nutrient-poor soils in semi-arid regions. Such genotypes conserve water before flowering and thus can alleviate post-flowering water stress, ensuring adequate P uptake despite low soil P availability.

• Klíčová slova
• Drought, Multiple resource limitations, Phosphorus, Plant phenological development, Sorghum, Water use,
• MeSH
• biomasa MeSH
• dusík metabolismus   MeSH
• fosfor * metabolismus   MeSH
• genotyp MeSH
• kořeny rostlin metabolismus   růst a vývoj   MeSH
• mykorhiza fyziologie   metabolismus   MeSH
• období sucha * MeSH
• půda * chemie   MeSH
• Sorghum * metabolismus   růst a vývoj   fyziologie   genetika   MeSH
• voda * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• fosfor * MeSH
• půda * MeSH
• voda * MeSH

Loss of the awn in some cereals, including sorghum, is a key transition during cereal domestication or improvement that has facilitated grain harvest and storage. The genetic basis of awn loss in sorghum during domestication or improvement remains unknown. Here, we identified the awn1 gene encoding a transcription factor with the ALOG domain that is responsible for awn loss during sorghum domestication or improvement. awn1 arose from a gene duplication on chromosome 10 that translocated to chromosome 3, recruiting a new promoter from the neighboring intergenic region filled with "noncoding DNA" and recreating the first exon and intron. awn1 acquired high expression after duplication and represses the elongation of awns in domesticated sorghum. Comparative mapping revealed high collinearity at the awn1 paralog locus on chromosome 10 across cereals, and awn growth and development were successfully reactivated on the rice spikelet by inactivating the rice awn1 ortholog. RNA-seq and DAP-seq revealed that as a transcriptional repressor, AWN1 bound directly to a motif in the regulatory regions of three MADS genes related to flower development and two genes, DL and LKS2, involved in awn development. AWN1 downregulates the expression of these genes, thereby repressing awn elongation. The preexistence of regulatory elements in the neighboring intergenic region of awn1 before domestication implicates that noncoding DNA may serve as a treasure trove for evolution during sorghum adaptation to a changing world. Taken together, our results suggest that gene duplication can rapidly drive the evolution of gene regulatory networks in plants.

• Klíčová slova
• DAP-seq, awn, gene duplication, sorghum domestication and improvement,
• MeSH
• chromozomy rostlin MeSH
• duplikace genu * MeSH
• jedlá semena anatomie a histologie   genetika   MeSH
• lokus kvantitativního znaku MeSH
• mapování chromozomů MeSH
• promotorové oblasti (genetika) MeSH
• proteinové domény MeSH
• regulace genové exprese u rostlin MeSH
• represorové proteiny genetika   fyziologie   MeSH
• rostlinné geny * MeSH
• rostlinné proteiny genetika   fyziologie   MeSH
• Sorghum anatomie a histologie   genetika   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• represorové proteiny MeSH
• rostlinné proteiny MeSH