Three awards at the X Tecnicaña Congress

In the field and industrial process categories, three works by professionals from Cenicaña stood out. Below are the summaries.

Field

First place: Diagnosis of yellow leaf virus (SCYLV, polerovirus) by real-time PCR (RT-qPCR)

Writers: Carolina Acosta V., Marcela Cadavid O., Juan Carlos Ángel S., Jorge Ignacio Victoria K. and Carlos Ariel Ángel C.

Sugar cane is the main crop planted in the Cauca river valley and is affected by various pathological problems such as yellow leaf virus (SCYLV). SCYLV (Polerovirus, Luteoviridae) is widely distributed worldwide and is transmitted by infected vegetative seed and by some vector aphid species.

For its diagnosis in tissue samples from leaves of commercial and seed lots, Cenicaña uses the reverse transcription molecular technique, followed by polymerase chain reaction (RT-PCR). With this technique, a qualitative result (presence / absence) is obtained if the compound sample is analyzed or the percentage of incidence of the disease is determined if each plant of a sample of twenty plants per batch is analyzed.

However, as it is a systemic condition, very low concentrations of the pathogen can occur, making its detection by RT-PCR difficult, and producing false negative results due to limits in the sensitivity of the techniques.

In this sense, the study carried out consisted in adapting and standardizing a more sensitive, rapid, specific and quantitative method for the diagnosis of SCYLV, which would also serve to analyze resistance in varieties in the future. Cenicaña currently has a real-time PCR protocol for SCYLV detection.

The β-Tubulin gene was also evaluated as a plant reference gene to monitor the quality of the RT-qPCR reaction, which proved to be constitutive and with little variation in its expression between healthy and diseased samples of the same variety and between varieties. , thus fulfilling the characteristics that are sought in a normalizing gene.

SCYLV was detected in up to 1.0 pg of total RNA from an infected plant. Finally, the higher sensitivity of RT-qPCR was validated with respect to the Tissue Blot Immuno Assay serological technique and conventional RT-PCR.

Second place: Expression of glutamine synthetase in assimilation of ammonium and nitrate in sugar cane

Writers: Claudia M. Franco, Hugo A. Jaimes, Fernando Muñoz, John J. Riascos, Héctor Chica and Jershon López.

The supply of ammonium and nitrate allows better growth of most plants; however, in large quantities, ammonia is toxic to plants.

Assimilation of ammonium (NH₄⁺) occurs thanks to the enzyme glutamine synthetase (GS). To evaluate the expression of GS using the real-time PCR technique, primers were designed and three varieties of sugarcane were used in hydroponic cultivation with two nutritive solutions: solution 1 = 85% NO₃^-/ 15% NH₄⁺ and solution 2 = 15% NO₃^-/ 85% NH₄⁺.

The plants were grown for 35 days in solution 1, and subsequently half of the plants were placed in solution 2. Root samples were taken at different times after the change of solutions (0, 4, 24 and 72 hours). For the relative expression analysis the gene of interest was GS1 and the reference gene was GAPDH.

It was found that at four hours GS1 had a higher expression in the roots of the three varieties evaluated. Expression patterns confirmed that sugarcane plants capture nitrogen in the roots, assimilate it, and thus avoid toxicity from excess ammonia.

Industrial processes

First place: Application of computational and experimental tools to improve grinding performance

Authors: Santiago Orduz, Julián Montes, Adolfo Gómez and Nicolás Gil.

Experiences and results in the development and application of experimental and computational tools to improve the extraction efficiency of mill tandems in the Colombian sugar sector.

With the implementation of the methodology in a pilot plant, benefits were observed in terms of reducing sucrose losses and decreasing the moisture content in bagasse.

This methodology emphasizes the diagnosis of the state of the stations, the adoption of technology, maintenance practices, the characteristics of the raw material, the stability of the processes and the assimilation of improvement approaches by all personnel involved in the operation.