Engineering food crops to grow in harsh environments

Abstract

Achieving sustainable agriculture and producing enough food for the increasing global population will require effective strategies to cope with harsh environments such as water and nutrient stress, high temperatures and compacted soils with high impedance that drastically reduce crop yield. Recent advances in the understanding of the molecular, cellular and epigenetic mechanisms that orchestrate plant responses to abiotic stress will serve as the platform to engineer improved crop plants with better designed root system architecture and optimized metabolism to enhance water and nutrients uptake and use efficiency and/or soil penetration. In this review we discuss such advances and how the generated knowledge could be used to integrate effective strategies to engineer crops by gene transfer or genome editing technologies.

Keywords: abiotic stress; bacterial genes; biotechnology; gene overexpression; grain yield; plant development; plant nutrition.

Figure 1.. Main targets for engineering crops for harsh environments

Engineering DRO1, AlaAT, PSTOL1, PTXD/Phi and the PHR1-Pi-SPX complex represent interesting approaches with the potential to improve crops for harsh environments. In addition, the identification and manipulation of genes involved in cell-wall components synthesis and stress-responsive epigenetic modifiers has great potential for developing optimal root systems and the improvement of plant responses to diverse stimuli. The simultaneous manipulation of some of these elements could bring robust effects to develop crops with high-yield performance, with a consequent decrease in P- and N-fertilizers input. C, cortex; E, endodermis; E´, epidermis; P, pericycle; VT, vascular tissue.

Figure 2.. Natural variation of Arabidopsis ecotypes in root penetration ability.

A) Col-0, Kz-9 and Ler Arabidopsis ecotypes show a wide variation in penetrating hard agar layers. Screening test was carried out using a double-phase agar system, which mimics soil compaction condition. B) Quantitative analysis of the root penetration ability expressed as the root penetration percentage (%) in reference to that of Col-0, showed by nine different Arabidopsis ecotypes. (*) indicates statistically significant differences: * P<0.05, ** P<0.01, and *** P<0.001 level; n=120 seedlings per ecotype (one-way ANOVA).