Successes and failures developing biotechnological tools in a model plant to improve crops. The long way from the growth chamber to the greenhouse and from the greenhouse to the field

JESICA RAINERI; RIBICHICH, KARINA F; MABEL CAMPI; MANUEL FRANCO; CABELLO, JULIETA V; MARÍA OTEGUI; RAQUEL L. CHAN

Congreso; Reunión de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2018

Worldwide research on Plant Molecular Biology has been carried out mostly working with model species. Among them, Arabidopsis thaliana is the most studied one due to several characteristics: first sequenced plant genome, short life cycle, small size, availability of genetic tools, etc. However, when the aim is to improve crops, using the knowledge acquired in such model, there is a long way full of obstacles and stop points to be traversed. An additional and independent complicated route is towards the front when traits tested in crops in a culture chamber need to be evaluated in a greenhouse and field trials. HaHB4 is a sunflower transcription factor, shown as able to confer drought and salinity tolerance in Arabidopsis. It was introduced as transgene in soybean and in wheat. Culture chamber, greenhouse and field trials in different environments were conducted indicating that beneficial traits were conserved between the model and the crops. This technology has almost ended the long way and soybean HaHB4 became a rare successful case because it is expected to be released to the market in 2018/2019. Data from last summer in Argentina, where a severe drought occurred, indicated variations in biomass and seed yield for transgenic HaHB4, control and commercial genotypes in three environments. Under heat stress or drought, seed yield of HaHB4 plants was always the largest (26%-95% yield increase), outyielded by the commercial line only in one well-watered environment. On the other hand and in spite of robust experimental results, wheat HaHB4 could not achieve the final goal; its release was stopped in the Agroindustry Ministry. Other sunflower transcription factors were introduced in crops aiming at testing their capability to promote benefits. In a few cases, the transgenes were not expressed as expected, probably due to inadequate genetic constructs used or silencing. HaHB11, which presents structural similarities with HaHB4, was shown as able to confer tolerance to flooding and increased yield in standard growth conditions. It was successfully introduced in maize, rice and soybean plants. Transgenic maize was assessed during two years in the greenhouse and in field trials showing increased biomass and yield at different extents. Transgenic HaHB11 rice was assessed only during one campaign showing promising results. Altogether, the assays performed with different transgenic technologies to improve crops performance indicated that once a technology is validated in a model, it is important to choose a suitable genetic construct and crop to transform and, most important, all the results must be classified as preliminary until repeated field trials are conducted in different environmental conditions.