Genetic and molecular characterisation of subtropically adapted low-phytate genotypes for utilisation in mineral biofortification of maize (

Abstract

Phytic acid (PA) is a major anti-nutritional factor in maize grains and significantly reduces the bioavailability of minerals such as iron and zinc in humans. Reduction of PA in maize (Zea mays L.) thus assumes great significance. Despite the availability of low phytic-acid (lpa) mutants in maize, their utilisation in breeding has been limited because of non-availability of well adapted lpa-based inbreds. A set of 24 subtropically adapted lpa1-1-based maize inbreds derived through molecular breeding was evaluated along with seven wild-type inbreds at multilocation. The lpa1-1 inbreds possessed 35.8% lower PA (1.68 mg/g) than the wild-type inbreds (2.61 mg/g). Mean proportion of PA was lower in the lpa1-1-based inbreds (62.8%) than in the wild-type inbreds (91.6%). The lpa1-1 inbreds showed similar performance for plant- and ear-height besides flowering behaviour as did wild types. Average grain yield among lpa1-1 inbreds (2735.9 kg/ha) was at par with the original versions (2907.3 kg/ha). Molecular profiling of these lpa1-1 inbreds using 60 genome-wide single-sequence repeats generated 172 alleles, with a mean of 2.87 alleles per locus. Mean polymorphism information content and mean gene diversity were 0.41 and 0.48 respectively. Genetic dissimilarity ranged from 0.23 to 0.81, with an average of 0.64. Cluster analyses grouped 24 lpa1-1 genotypes into three major clusters, and principal-coordinate analysis depicted the diverse nature of genotypes. The study also identified a set of potential hybrid combinations with low PA for their direct utilisation in biofortification program. This is the first study on comprehensive characterisation of lpa1-1-based inbreds adapted to subtropical conditions.

Genetic variation for grain phytate and molecular characterization of low phytic acid‐2 (lpa2) gene‐based maize (Zea mays) inbreds

“…Significant variation for all the biochemical parameters among the lpa2‐1 mutant and wild‐type inbreds observed in the study indicates the scope for exploitation of these low phytate maize inbreds to develop low phytate maize hybrids. The mean low PA and PAP/TP ratio among the lpa2‐1 ‐based inbreds suggested the scope of their utilization as parents in the breeding programme (Abhijith et al, 2020; Ragi et al, 2021; Yathish et al, 2021). The proportion of PA reduction (~26%) observed among the inbreds analysed under the present study was at par with reduction (30%) reported by Shi et al (2003).…”

“…Genetic diversity analyses based on molecular markers enable to study the genetic relatedness between the genotypes more efficiently. SSR markers are popular choice for diversity study in maize (Pandey et al, 2016; Ragi et al, 2021). The study revealed wide diversity among the lpa2 ‐based inbreds used in the study.…”

“…Thus, our study clearly demonstrated that lpa2‐1 ‐based inbreds were at par with the wild‐type inbreds for key agronomic characters and grain yield. Ragi et al (2021) analysed a set of lpa1‐1 ‐based maize inbreds with ~36% reduction of PA and reported that mutant inbreds were quite similar with the wild‐type inbreds in relation to various agronomic traits and grain yield. Thus, lpa2‐1 ‐based inbreds can be successfully utilized for development and commercial cultivation of low phytate maize hybrids.…”

Mineral biofortification and metal/metalloid accumulation in food crops: recent research and trends (Part I)

“…From a population of doubled haploid lines of wheat, Lephuthing et al (2022) identified 15 lines (high in Fe, Zn and yield) for future research. Regarding selection of lowantinutrient genotypes, Ragi et al (2022) identified several promising maize hybrids produced from inbred lines of wildtype and subtropically adapted low-phytate mutants (lpa1-1). In addition to the above genetic approaches, Ibrahim et al (2022) argued that precise genome editing tools (such as CRISPR/Cas9) can deliver new micronutrient biofortified cultivars with no linkage-drag and biosafety issues.…”

Quality protein maize: nutritional and bioactive composition, technological attributes and potential food applications

“…Several traits related to synthesis of Fe and Zn (Chakraborti et al ., 2011), provitamin A (Mallikarjuna et al ., 2014), provitamin A and vitamin E (Zunjare et al ., 2018) have been successfully incorporated into different QPM varieties providing them an additional advantage of coping with micronutrient deficiencies. Also, QPM with waxy nature (Yang et al ., 2013), popping character (Ren et al ., 2018) and low phytate (Ragi et al ., 2021) content have been developed. Nutritive properties of QPM are shown in Table 1.…”