Increasing protein content and digestibility in sorghum grain with a synthetic biology approach

Abstract

Despite great genetic diversity, sorghum grain consistently suffers from poor protein digestibility. The physicochemical packaging of protein bodies which consist of proteaseresistant βand γ-kafirin is considered a major obstacle. A synthetic β-kafirin gene, which shares the endosperm-specific promoter and signal peptide with the native β-kafirin gene (Sobic.009G001600.1), was transformed into sorghum inbred line Tx430. The gene was modified with ten additional proteolytic sites. These sites were designed to be amenable to cleavage by pepsin and/or chymotrypsin proteinases. Five independent transgenic lines were regenerated by microprojectile transformation. Notably, considerably more protein was observed in the peripheral endosperm of transgenic lines under scanning electron microscopy. Microscopy revealed invaginated or irregularly shaped protein bodies in the endosperm of transgenic lines. Grains of transgenic lines contained 11-37% more protein, which was 11-21% more pepsin digestible and 7-25% more chymotrypsin digestible than Tx430. Additionally, the abundant synthetic β-kafirin protein (5.6% of total protein) was detected by mass spectrometry data analysis in the transgenic line 9-1. Field-grown homozygous transgenics retained higher protein content, larger seed size and no reduction in grain number per plant. The results illustrated that plant synthetic biology could play an important role in improving sorghum nutritional value.

Trends in Synthetic Biology in the Bioeconomy of Non-food-Competing Biofuels

“…Having overcome the challenges, synthetic biology could reach and cover not only the biofuel supply chain but also other areas that form agribusiness, with greater added value [146]. The synthetic biology tools applied to microorganisms offer the possibility of producing chemicals for agricultural production that can increase agricultural productivity [147], give greater nutritional value to agricultural products [148], and benefit the environment [149]. Bio-factories can also be used to make substances currently produced by plants for food [150], medicine [151,152], among other sectors.…”

Kajian Substitusi Kacang Komak (Lablab Purpureus (L.) Sweet) Terhadap Nasi Kecambah Sorgum Merah

“…Tanin merupakan zat antinutrisi yang harus direduksi atau diturunkan karena dapat menurunkan daya cerna protein dari nasi sorgum tersebut. Struktur tannin-protein memiliki molekul yang sangat besar, memiliki sejumLah gugus hidroksil dan memiliki banyak cincin hidrofobik yang cukup besar (Liu et al 2019). Penurunkan kadar tanin dapat dilakukan dengan perendaman dan perkecambahan.…”

Large and stable genome edits at the sorghum alpha kafirin locus result in changes in chromatin accessibility and globally increased expression of genes encoding lysine enrichment

“…Of consequence to sorghum’s nutritional value, the outer protein body fraction is less digestible than the alpha-kafirin core as a result of cross-linking between kafirin species ( Oria et al., 1995 ; Duodu et al., 2003 ). As a result, mutants or transgenic constructs which modify kafirins have been shown to alter protein bodies in a manner which makes them more digestible ( Da Silva et al., 2011 ; Kumar et al., 2012 ; Cremer et al., 2014 ; Grootboom et al., 2014 ; Liu et al., 2019 ). One such kafirin allele, a characterized mutation in the alpha-kafirin signal peptide causes abnormal protein body formation and reduced alpha-kafirin accumulation ( Tesso et al., 2006 ; Wu et al., 2013 ).…”