Registration of NPM-4, a Dwarf White Grain Pearl Millet Germplasm

Dwarf grain pearl millet [Pennisetum glucum (L.) R. Br.] germplasm NPM-4 (Reg. no. GP-37, PI 634545) was released in September 2003 by the Institute of Agriculture and Natural Resources, University of Nebraska, Lincoln, NE. NPM-4 was derived from open-pollinated outcrosses of white grain inbred line 57028R1w grown in a 1998 Puerto Vallarta winter nursery. The source of the outcross pollen was from primarily genetically diverse, dwarf, early maturing, gray seeded lines being developed as parents for grain yield. Line 57028R1w was derived from 89C57028R1/3*90PV0121. Line 89C57028R1 is gray-seeded, and line 90PV0121 has white seed. Line 90PV0121, an F5 was derived from the cross 85C53005/ZW10. Line 89C57028R1was an A1 (Burton, 1958) cytoplasmic nuclear male-sterility (cms) restorer S5 selection out of row 84M:17101-1 of segregating germplasm obtained in the late 1970s from Dr. A.J. Casady, Kansas State University, that had undergone random mating and selection for at least 3 cycles before 1984. Line 85C53005 was an A1 maintainer S2 selection (84H:14014) also from the segregating Casady germplasm. The line ZW10 was a white seeded introduction from Zambia obtained in 1988. The 1998 winter nursery outcrosses of 57028R1w were grown in isolation at the Department of Agronomy Farm at the University of Nebraska’s Agricultural Research and Development Center (ARDC), Mead, NE, in 1998 and productive dwarf white seeded plants were selected for harvest and bulked together. The harvested bulk was grown in 1999 at Mead and plants were selfed and selected for all white seed on panicles. The white seeded selfs were grown in isolation in 2000. Nineteen open-pollinated white grain selections were made and random mated in isolation in 2001. Open pollinated seed of the best six white grain families was combined to form the bulk for seed release. Final selection was for panicle size, kernel size, and lodging resistance. Top-crosses of NPM-4 with cms lines NE68A1, NE59043A1, and KS1163A1 (a CMS A1–line from W.D. Stegmeier, Kansas State University-Hays) in 2002 indicated that NPM-4 was a good restorer of A1 cms with good combining ability for grain yield

Tonoplast Sugar Transporters (SbTSTs) Putatively Control Sucrose Accumulation in Sweet Sorghum Stems

Carbohydrates are differentially partitioned in sweet versus grain sorghums. While the latter preferentially accumulate starch in the grain, the former primarily store large amounts of sucrose in the stem. Previous work determined that neither sucrose metabolizing enzymes nor changes in Sucrose transporter (SUT) gene expression accounted for the carbohydrate partitioning differences. Recently, 2 additional classes of sucrose transport proteins, Tonoplast Sugar Transporters (TSTs) and SWEETs, were identified; thus, we examined whether their expression tracked sucrose accumulation in sweet sorghum stems. We determined 2 TSTs were differentially expressed in sweet vs. grain sorghum stems, likely underlying the massive difference in sucrose accumulation. A model illustrating potential roles for different classes of sugar transport proteins in sorghum sugar partitioning is discussed

Tonoplast Sugar Transporters (SbTSTs) Putatively Control Sucrose Accumulation in Sweet Sorghum Stems

Carbohydrates are differentially partitioned in sweet versus grain sorghums. While the latter preferentially accumulate starch in the grain, the former primarily store large amounts of sucrose in the stem. Previous work determined that neither sucrose metabolizing enzymes nor changes in Sucrose transporter (SUT) gene expression accounted for the carbohydrate partitioning differences. Recently, 2 additional classes of sucrose transport proteins, Tonoplast Sugar Transporters (TSTs) and SWEETs, were identified; thus, we examined whether their expression tracked sucrose accumulation in sweet sorghum stems. We determined 2 TSTs were differentially expressed in sweet vs. grain sorghum stems, likely underlying the massive difference in sucrose accumulation. A model illustrating potential roles for different classes of sugar transport proteins in sorghum sugar partitioning is discussed

An efficient and improved method for virus-induced gene silencing in sorghum

Background: Although the draft genome of sorghum is available, the understanding of gene function is limited due to the lack of extensive mutant resources. Virus-induced gene silencing (VIGS) is an alternative to mutant resources to study gene function. This study reports an improved and efficient method for Brome mosaic virus (BMV)-based VIGS in sorghum. Methods: Sorghum plants were rub-inoculated with sap prepared by grinding 2 g of infected Nicotiana benthamiana leaf in 1 ml 10 mM potassium phosphate buffer (pH 6.8) and 100 mg of carborundum abrasive. The sap was rubbed on two to three top leaves of sorghum. Inoculated plants were covered with a dome to maintain high humidity and kept in the dark for two days at 18 °C. Inoculated plants were then transferred to 18 °C growth chamber with 12 h/12 h light/dark cycle. Results: This study shows that BMV infection rate can be significantly increased in sorghum by incubating plants at 18 °C. A substantial variation in BMV infection rate in sorghum genotypes/varieties was observed and BTx623 was the most susceptible. Ubiquitin (Ubiq) silencing is a better visual marker for VIGS in sorghum compared to other markers such as Magnesium Chelatase subunit H (ChlH) and Phytoene desaturase (PDS). The use of antisense strand of a gene in BMV was found to significantly increase the efficiency and extent of VIGS in sorghum. In situ hybridization experiments showed that the non-uniform silencing in sorghum is due to the uneven spread of the virus. This study further demonstrates that genes could also be silenced in the inflorescence of sorghum. Conclusion: In general, sorghum plants are difficult to infect with BMV and therefore recalcitrant to VIGS studies. However, by using BMV as a vector, a BMV susceptible sorghum variety, 18 °C for incubating plants, and antisense strand of the target gene fragment, efficient VIGS can still be achieved in sorghum

Estimation of the Degree of Diversity for Some Iraqi Wheat Varieties through ISSR, SRAP and RAPD Markers

DNA-based molecular markers such as Inter Simple Sequence Repeat (ISSR), Sequence-Related Amplified polymorphism (SRAP) and Random Amplified Polymorphic DNA (RAPD) were used in this study to examine the genetic differences among sixteen Iraqi wheat varieties. Seventy three primers out of 177 were reproducible and showed clear amplified bands. The degree of genetic diversity, Polymorphism information content (PIC) and resolving power (RP) were estimated. All the studied molecular markers were informative and showed good ability to classify and distinguish 16 wheat varieties. Total number of polymorphic bands is 134, 221 and 55 for ISSR, SRAP and RAPD respectively. PIC and RP values were 0.259, 0.264 and 0.262 and 9.06, 7.87 and 2.7

Grain sorghum whole kernel oil lowers plasma and liver cholesterol in male hamsters with minimal wax involvement

The lipid fraction of the grain sorghum whole kernel (GS-WK) (i.e., phytosterol rich oil or policosanol rich wax) responsible for lowering cholesterol in hamsters fed the crude lipid (wax + oil) was determined. As expected, hamsters fed an atherogenic diet for a four week period presented with higher plasma non-HDL plasma and liver esterified cholesterol than those on the low fat diet. However, the atherogenic diet containing 5% (w/w) oil significantly lowered non-HDL plasma and liver cholesterol. Although the 5% wax supplement did not affect either plasma or liver cholesterol, excreted neutral sterol and bile acid were slightly higher than produced by the atherogenic diet. Still, cholesterol excretion negatively correlated with liver cholesterol concentration (r = –0.681, p \u3c 0.001) across diets with the oil fraction producing the greatest impact. These combined results indicate that oil plays the most significant role in modulating cholesterol, most likely by inhibiting absorption, but subtle interactions by the wax may be involved. However, the sorghum oil would be the most potent component to serve as a possible heart health ingredient in functional foods

Implementation of Epigenetic Variation in Sorghum Selection and Implications for Crop Resilience Breeding

Crop resilience and yield stability are complex traits essential for food security. Sorghum bicolor is an important grain crop that shows promise for its natural resilience to drought and potential for marginal land production. We have developed sorghum lines in the Tx430 genetic background suppressed for MSH1 expression as a means of inducing de novo epigenetic variation, and have used these materials to evaluate changes in plant growth vigor. Plant crossing and selection in two distinct environments revealed features of phenotypic plasticity derived from MSH1 manipulation. Introduction of an epigenetic variation to an isogenic sorghum population, in the absence of selection, resulted in 10% yield increase under ideal field conditions and 20% increase under extreme low nitrogen conditions. However, incorporation of early-stage selection amplified these outcomes to 36% yield increase under ideal conditions and 64% increase under marginal field conditions. Interestingly, the best outcomes were derived by selecting mid-range performance early-generation lines rather than highest performing. Data also suggested that phenotypic plasticity derived from the epigenetic variation was nonuniform in its response to environmental variability but served to reduce genotype x environment interaction. The MSH1-derived growth vigor appeared to be associated with enhanced seedling root growth and altered expression of auxin response pathways, and plants showed evidence of cold tolerance, features consistent with observations made previously in Arabidopsis. These data imply that the MSH1 system is conserved across plant species, pointing to the value of parallel model plant studies to help devise effective plant selection strategies for epigenetic breeding in multiple crops

Validation of QTL mapping and transcriptome profiling for identification of candidate genes associated with nitrogen stress tolerance in sorghum

Background: Quantitative trait loci (QTLs) detected in one mapping population may not be detected in other mapping populations at all the time. Therefore, before being used for marker assisted breeding, QTLs need to be validated in different environments and/or genetic backgrounds to rule out statistical anomalies. In this regard, we mapped the QTLs controlling various agronomic traits in a recombinant inbred line (RIL) population in response to Nitrogen (N) stress and validated these with the reported QTLs in our earlier study to find the stable and consistent QTLs across populations. Also, with Illumina RNA-sequencing we checked the differential expression of gene (DEG) transcripts between parents and pools of RILs with high and low nitrogen use efficiency (NUE) and overlaid these DEGs on to the common validated QTLs to find candidate genes associated with N-stress tolerance in sorghum. Results: An F7 RIL population derived from a cross between CK60 (N-stress sensitive) and San Chi San (N-stress tolerant) inbred sorghum lines was used to map QTLs for 11 agronomic traits tested under different N-levels. Composite interval mapping analysis detected a total of 32 QTLs for 11 agronomic traits. Validation of these QTLs revealed that of the detected, nine QTLs from this population were consistent with the reported QTLs in earlier study using CK60/China17 RIL population. The validated QTLs were located on chromosomes 1, 6, 7, 8, and 9. In addition, root transcriptomic profiling detected 55 and 20 differentially expressed gene (DEG) transcripts between parents and pools of RILs with high and low NUE respectively. Also, overlay of these DEG transcripts on to the validated QTLs found candidate genes transcripts for NUE and also showed the expected differential expression. For example, DEG transcripts encoding Lysine histidine transporter 1 (LHT1) had abundant expression in San Chi San and the tolerant RIL pool, whereas DEG transcripts encoding seed storage albumin, transcription factor IIIC (TFIIIC) and dwarfing gene (DW2) encoding multidrug resistance-associated protein-9 homolog showed abundant expression in CK60 parent, similar to earlier study. Conclusions: The validated QTLs among different mapping populations would be the most reliable and stable QTLs across germplasm. The DEG transcripts found in the validated QTL regions will serve as future candidate genes for enhancing NUE in sorghum using molecular approaches

Molecular and phenotypic characterization of transgenic wheat and sorghum events expressing the barley alanine aminotransferase

Main conclusion — The expression of a barley alanine aminotransferase gene impacts agronomic outcomes in a C3 crop, wheat. The use of nitrogen-based fertilizers has become one of the major agronomic inputs in crop production systems. Strategies to enhance nitrogen assimilation and flux in planta are being pursued through the introduction of novel genetic alleles. Here an Agrobacterium-mediated approach was employed to introduce the alanine aminotransferase from barley (Hordeum vulgare), HvAlaAT, into wheat (Triticum aestivum) and sorghum (Sorghum bicolor), regulated by either constitutive or root preferred promoter elements. Plants harboring the transgenic HvAlaAT alleles displayed increased alanine aminotransferase (alt) activity. The enhanced alt activity impacted height, tillering and significantly boosted vegetative biomass relative to controls in wheat evaluated under hydroponic conditions, where the phenotypic outcome across these parameters varied relative to time of year study was conducted. Constitutive expression of HvAlaAT translated to elevation in wheat grain yield under field conditions. In sorghum, expression of HvAlaAT enhanced enzymatic activity, but no changes in phenotypic outcomes were observed. Taken together these results suggest that positive agronomic outcomes can be achieved through enhanced alt activity in a C3 crop, wheat. However, the variability observed across experiments under greenhouse conditions implies the phenotypic outcomes imparted by the HvAlaAT allele in wheat may be impacted by environment

HERBICIDE RESISTANTSORGHUM MUTANTS

This disclosure provides for four different sorghum mutants that exhibit resistance to ALS-inhibiting herbicides. This dis closure also provides for methods of using such Sorghum mutants that exhibit resistance to ALS-inhibiting herbicides in breeding methods to make Sorghum hybrids, varieties, or lines. The Sorghum hybrids, varieties, and lines provided in this disclosure can be used in methods of controlling weeds