Plant Science Seminar Series
Can Genetic Modified Wheat Help People Escape Hunger in the Future?
On 6 October, Dr. Vijay Tiwari spoke to us about his work on the wheat genome. Dr. Tiwari completed his PhD in 2009 in Plant Biotechnology from Indian Institute of Technology Roorkee, one of the premier institutes of higher learning in India. After that he joined Oregon State University as a postdoctoral scientist to work on an NSF-funded project on radiation hybrid (RH) based physical mapping of D-genome chromosomes of wheat. During his stay in OSU, he developed an innovative approach to physically map wheat chromosomes using radiations, for which he received Early Career Award at International Triticeae Mapping Initiative in 2012. Towards the end of 2012, he joined Dr. Bikram Gill at Kansas State University (KSU) to lead and coordinate research at an NSF supported Industry-University Partnership Center, also known as WGRC. Recently, Dr. Tiwari joined the faculty at the University of Maryland, College Park. Dr. Tiwari gave an impressive talk entitled, Applications of genomic approaches for global food security.
During his presentation, Dr. Tiwari showcased the multiple projects undertaken by his research team at KSU. The highlights of his talk were RH mapping to assist reference wheat genome sequencing, genomics for crop improvement, and alien chromosome based genomics. Dr. Tiwari started his talk stating the major problems and challenges associated with wheat production. He said that, “wheat production is severely affected by abiotic stresses (such as heat, drought and salinity) and biotic stresses (such as plant diseases and pests)”. Despite these challenges, wheat production may need to increase to meet food demands of an ever-increasing human population. No easy task, and even more difficult considering future climate conditions (elevated temperature and carbon dioxide levels) and reduced land for agriculture.
Novel genomic approaches might potentially improve crop production and help bridge the food gap. For this, the first and the most basic thing to do is to sequence the wheat genome in order to identify the genes associated with favorable traits. As per him, the wheat genome sequence will be available by early 2017.
Dr. Tiwari and his team worked on RH mapping in wheat, which can fix a major problem associated with genetic mapping and map based cloning studies in low recombination regions in wheat. Radiation hybrid (RH) mapping, a physical mapping approach, is based on radiation-induced chromosome breakage and a reconstruction of marker order based on their co-retention patterns. Recently he and his team developed a whole genome RH mapping (WGRH) resource and used high density marker genotyping arrays, to show the potential of RH mapping in genome mapping and analysis using a small mapping population. He said, “RH can improve gene mapping and map-based cloning in wheat as it relies on radiation-induced breaks to order markers and RH resource we developed will be an incredible resource for wheat genetics and genomics community”. His team also developed high-resolution physical maps of D-genome chromosomes in wheat. The RH mapping resource has been used by his team to validate reference assembly of wheat chromosome 3B (Tiwari et al., 2016).
Dr. Tiwari suggested that genomics approaches can be used to develop improved crops. He mentioned that distant gene pool of wheat is an excellent source for genes and alleles to overcome challenges posed by biotic and abiotic stresses for sustainable increase in wheat production. However, the transfer of genes among crop species is affected by suppressed recombination, limited marker availability, and lack of genomic resources. Availability of high density molecular markers can help to identify small to large useful translocations from distant wild wheat species (Tiwari et al, 2015) and his recent work on chromosome 5M of Aegilops geniculata clearly supported it. Genomic resources will immensely help breeders and crop scientists to transfer important genes and alleles from wild and related gene pool of crop plants with very reduced linkage drag.
Wheat is a major food crop that supplies bulk of the human food calories. Therefore, improving wheat production will play a key role in our efforts towards attaining global food security. I believe researches undertaken by Dr. Tiwari and his team at KSU will definitely have a significant effect in global wheat production.
Tiwari VK, Heesacker A, et al., 2016. A whole-genome, radiation hybrid mapping resource of hexaploid wheat. Plant Journal, 2:195-207.
Tiwari, V K, Wang, S, et al., 2015. Exploring the tertiary gene pool of bread wheat: sequence assembly and analysis of chromosome 5Mg of Aegilops geniculata. Plant J, 84: 733–746.
By Xingchen Liu
Edited by Resham Thapa, Katherine Tully
Figure 2. Presentation of RH mapping using marker-based dissection of wheat chromosomes 5D. The dissection of chromosome 5D is based on the pattern of marker retention or loss in a panel. Solid blue squares indicate that a marker is present in a given RH panel member. Solid yellow squares indicate that a marker was absent in a given RH panel member. Missing data is presented by empty white squares. The order of the DNA markers is based on genetic consensus maps (left of each figure) reported by Somers et al. [2004]. Interrelationship between linkage maps and RH data is shown by connecting lines. The deletion bin maps (right of each figure) are based on Sourdille et al. [2004]. The correspondence between DGRH data and the deletion bin maps is shown by connecting lines.
