Transcriptome Analysis of Drought Induced Stress in <i>Chenopodium quinoa</i>

Abstract

Quinoa (Chenopodium quinoa Willd.) is a halophytic, allotetraploid grain crop of the Amaranthaceae family with impressive drought tolerance, nutritional content and an increasing worldwide market. Here we report the results of an RNA-seq transcriptome analysis of Chenopodium quinoa using four water treatments (field capacity to drought) on the varieties "Ingapirca" (representing valley ecotypes) and "Ollague" (representing Altiplano Salares ecotypes). Physiological results, including growth rate, photosynthetic rate, stomatal conductance, and stem water potential, support the earlier findings that the Altiplano Salares ecotypes display greater tolerance to drought-like stress conditions than the valley ecotypes. cDNA libraries from root tissue samples for each variety × treatment combination were sequenced using Illumina Hi-Seq technology in an RNA-seq experiment. De novo assembly of the transcriptome generated 20,337 unique transcripts. Gene expression analysis of the RNA-seq data identified 462 putative gene products that showed differential expression based on treatment, and 27 putative gene products differentially expressed based on variety × treatment, including significant expression differences in root tissue in response to increasing water stress. BLAST searches and gene ontology analysis show an overlap between drought tolerance stress and other abiotic stress mechanisms.

Quinoa: In Perspective of Global Challenges

“…Other harsh environmental conditions that are increasing as a result of climate change are drought and desertification, which are factors that negatively influence crop productivity worldwide [1,[51][52][53][54]. Annually, human activity and climate change result in drying up of about~12 million hectares of productive land, thus transforming it into a barren state due to desertification and drought and causing more than one-third of the world's population to inhabit water-stressed areas [1,54].…”

Salt bladders: do they matter?

“…There is also compelling bulk of evidence suggesting that transgenic plant expressing well selected ion transporter and pumps seem to gain increased salt tolerance [38,39]. Thus, while indeed manipulating with a set of genes is a rather challenging task, we see no reasons of why the above knowledge cannot be used for crop design strategies, given the recent availability of the genome/transcriptome information of the Amaranthaceae/ Chenopodiaceae spinach, sugar beet, and quinoa species [40,41]. This opens exciting possibilities for modifying trichome shape, size, density, and salt storage capacity in conventional crops ( Figure 3) by introducing salt-induced, targeted trichome-bladder transition and its linked Na + /Cl À sequestration function.…”

Genetic diversity in tef [Eragrostis tef (Zucc.) Trotter]

“…An RNA-Seq study of two different varieties of quinoa (Raney et al, 2014), one representing valley ecotypes and another one representing high plains ecotypes, under different watering conditions was recently conducted. It was found that 27 putative gene products were differentially expressed based on variety × treatment interaction.…”