Pyramiding of genes for grain protein content, grain quality, and rust resistance in eleven Indian bread wheat cultivars: a multi-institutional effort

Improvement of grain protein content (GPC), loaf volume, and resistance to rusts was achieved in 11 Indian wheat cultivars that are widely grown in four different agro-climatic zones of India. This involved use of marker-assisted backcross breeding (MABB) for introgression and pyramiding of the following genes: (i) the high GPC gene Gpc-B1; (ii) HMW glutenin subunits 5 + 10 at Glu-D1 loci, and (iii) rust resistance genes, Yr36, Yr15, Lr24, and Sr24. GPC increased by 0.8 to 3.3%, although high GPC was generally associated with yield penalty. Further selection among high GPC lines allowed identification of progenies with higher GPC associated with improvement in 1000-grain weight and grain yield in the backgrounds of the following four cultivars: NI5439, UP2338, UP2382, and HUW468. The high GPC progenies (derived from NI5439) were also improved for grain quality using HMW glutenin subunits 5 + 10 at Glu-D1 loci. Similarly, progenies combining high GPC and rust resistance were obtained in the backgrounds of following five cultivars: Lok1, HD2967, PBW550, PBW621, and DBW1. The improved pre-bred lines developed following multi-institutional effort should prove a valuable source for the development of cultivars with improved nutritional quality and rust resistance in the ongoing wheat breeding programmes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11032-022-01277-w.

Association of air pollution and homocysteine with global DNA methylation: A population-based study from North India

BACKGROUND

Anthropogenic air pollution has been implicated in aberrant changes of DNA methylation and homocysteine increase (>15μM/L). Folate (<3 ng/mL) and vitamin B12 (<220 pg/mL) deficiencies also reduce global DNA methylation via homocysteine increase. Although B-vitamin supplements can attenuate epigenetic effects of air pollution but such understanding in population-specific studies are lacking. Hence, the present study aims to understand the role of air pollution, homocysteine, and nutritional deficiencies on methylation.

METHODS

We examined cross-sectionally, homocysteine, folate, vitamin B12 (chemiluminescence) and global DNA methylation (colorimetric ELISA Assay) among 274 and 270 individuals from low- and high- polluted areas, respectively, from a single Mendelian population. Global DNA methylation results were obtained on 254 and 258 samples from low- and high- polluted areas, respectively.

RESULTS

Significant decline in median global DNA methylation was seen as a result of air pollution [high-0.84 (0.37-1.97) vs. low-0.96 (0.45-2.75), p = 0.01]. High homocysteine in combination with air pollution significantly reduced global DNA methylation [high-0.71 (0.34-1.90) vs. low-0.93 (0.45-3.00), p = 0.003]. Folate deficient individuals in high polluted areas [high-0.70 (0.37-1.29) vs. low-1.21 (0.45-3.65)] showed significantly reduced global methylation levels (p = 0.007). In low polluted areas, despite folate deficiency, if normal vitamin B12 levels were maintained, global DNA methylation levels improved significantly [2.03 (0.60-5.24), p = 0.007]. Conversely, in high polluted areas despite vitamin B12 deficiency, if normal folate status was maintained, global DNA methylation status improved significantly [0.91 (0.36-1.63)] compared to vitamin B12 normal individuals [0.54 (0.26-1.13), p = 0.04].

CONCLUSIONS

High homocysteine may aggravate the effects of air pollution on DNA methylation. Vitamin B12 in low-polluted and folate in high-polluted areas may be strong determinants for changes in DNA methylation levels. The effect of air pollution on methylation levels may be reduced through inclusion of dietary or supplemented B-vitamins. This may serve as public level approach in natural settings to prevent metabolic adversities at community level.