Introducción

El tomate (Solanum lycopersicum L.) constituye la segunda especie de importancia dentro del género Solanum spp., por su papel en los hábitos alimenticios de gran parte de la población mundial (11. Bayomi KEM, Abdel-Baset A, Nasar SMA, Al-Kady AEMA. Performance of some tomato genotypes under greenhouse conditions. Egyptian Journal of Desert Research. 2020;70(1):1-10. https://doi.org/10.21608/EJDR.2019.16947.1041 , 22. Monge-Pérez JE, Loría-Coto M. Determinación de criterios de selección para el rendimiento de tomate (Solanum lycopersicum L) cultivado bajo invernadero. AIA Avances en Investigación Agropecuaria. 2022;25(1):7-19.). Sin embargo, el rendimiento del cultivo se afecta seriamente por condiciones medioambientales adversas, fundamentalmente estrés hídrico y temperaturas extremas (33. Jiang X, Zhao Y, Tong L, Wang R, Zhao S. Quantitative analysis of tomato yield and comprehensive fruit quality in response to deficit irrigation at different growth stages. HortScience. 2019;54(8):1409-1417. https://doi.org/10.21273/HORTSCI14180-19 , 44. Sousaraei N, Mashayekhi K, Mousavizadeh SJ, Akbarpour V, Medina J, Aliniaeifard S. Screening of tomato landraces for drought tolerance based on growth and chlorophyll fluorescence analyses. Horticulture, Environment, and Biotechnology. 2021;62:521-535. https://doi.org/10.1007/s13580-020-00328-5 ).

El estrés hídrico afecta los procesos de transpiración, fotosíntesis, apertura de estomas, temperatura de las hojas y metabolismo antioxidante; estos cambios metabólicos alteran el desarrollo de la planta y comprometen su producción y rendimiento (55. Kumar V, Datir S, Khare T, Shriram V. Advances in biotechnological tools: Improving abiotic stress tolerance in rice. In: Hasanuzzaman M, Fujita M, Nahar K, Biswas JK, editors. Advances in Rice Research for Abiotic Stress Tolerance. Sawston, CA, USA: Elsevier Inc. 2019; Chapter 30:615-632. https://doi.org/10.1016/B978-0-12-814332-2.00030-7 -77. Méndez-Vázquez JR, Benavides-Mendoza A, Juárez-Maldonado A, Cabrera-De la Fuente M, Robledo-Olivo A, González-Morales S. Efecto del riego deficitario en la acumulación de compuestos antioxidantes en plantas de tomate. Ecosistemas y Recursos Agropecuarios. 2021;8(2):e2822. https://doi.org/10.19136/era.a8n2.2822 ). Diversos estudios señalan que las membranas son el lugar donde se producen la mayoría de las afectaciones por estrés en las plantas. Las pérdidas en la integridad de la membrana por estrés hídrico se han evaluado midiendo mayormente la estabilidad de la membrana, y en menor medida por la fuga de sustancias absorbentes de la radiación UV, incluyendo aminoácidos, nucleósidos y nucleótidos (44. Sousaraei N, Mashayekhi K, Mousavizadeh SJ, Akbarpour V, Medina J, Aliniaeifard S. Screening of tomato landraces for drought tolerance based on growth and chlorophyll fluorescence analyses. Horticulture, Environment, and Biotechnology. 2021;62:521-535. https://doi.org/10.1007/s13580-020-00328-5 , 88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x -1212. Nijabat A, Bolton A, Mahmood-ur-Rehman M, Shah AI, Hussain R, Naveed RH, Ali A, Simon P. Cell membrane stability and relative cell injury in response to heat stress during early and late seedling stages of diverse carrot (Daucus carota L.) germplasm. HortScience. 2020;55(9):1446-1452. https://doi.org/10.21273/HORTSCI15058-20 ). La pérdida de sustancias absorbentes de UV se ha utilizado para evaluar la tolerancia relativa al estrés salino de los tejidos vegetales, no así en evaluaciones del estrés hídrico (44. Sousaraei N, Mashayekhi K, Mousavizadeh SJ, Akbarpour V, Medina J, Aliniaeifard S. Screening of tomato landraces for drought tolerance based on growth and chlorophyll fluorescence analyses. Horticulture, Environment, and Biotechnology. 2021;62:521-535. https://doi.org/10.1007/s13580-020-00328-5 , 88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x ).

En estudios de simulación del estrés hídrico en condiciones de laboratorio se utiliza con frecuencia el polietilenglicol (PEG). El PEG es un alcohol polimérico con alta solubilidad en agua y baja toxicidad que actúa como agente osmótico no penetrante al disminuir el potencial hídrico del medio de cultivo; produce una deficiencia hídrica en las células vegetales y un desbalance del metabolismo en general (1313. Pastelín-Solano MC, Castañeda-Castro O. Afectaciones fisiológicas y bioquímicas en vitroplantas de caña de azúcar en respuesta al estrés hídrico y salino. Revista Mexicana de Ciencias Agrícolas. 2018;9(7):1483-1493. https://doi.org/10.29312/remexca.v9i7.1253 ).

Con base en lo anterior, y debido a la necesidad de buscar técnicas que puedan utilizarse como pruebas estandarizadas para la tolerancia al déficit hídrico, se realizó el presente trabajo con el objetivo de evaluar la tolerancia a este estrés en tejido foliar de 22 accesiones de tomate mediante la determinación relativa del eflujo de sustancias que absorben la radiación UV, con la finalidad de identificar accesiones tolerantes para la selección y uso en programas de mejoramiento genético.

Materiales y métodos

Para determinar el eflujo de iones que absorben en la radiación UV, se colectaron 15 discos al azar de aproximadamente 90 mm de diámetro, de la segunda hoja verdadera de plántulas de 21 días para 22 accesiones de tomate; se realizaron cuatro réplicas por tratamiento (Tabla 1). El tejido vegetal se colocó en viales de 10 mL, se lavaron tres veces con agua destilada para eliminar los iones externos que pudieran ser liberados después del corte. Enseguida, se sumergieron en 2 mL de agua destilada (tratamiento control) y 2 mL de solución de PEG 6000 a 2 mPa (tratamiento de estrés), y se dejaron reposar en total oscuridad a 25 °C durante toda una noche. Posteriormente, se midió la densidad óptica a 280 nM con un espectrofotómetro Genesys 10. El eflujo de fenoles se calculó con la fórmula siguiente (88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x ):

Donde:

EF: Eflujo de fenoles

DO estrés: valores de densidad óptica de los tratamientos de estrés

DO control: valores de densidad óptica de los tratamientos control

El experimento se realizó por duplicado. Los datos fueron procesados por ANOVA de clasificación simple, modelo efectos fijos y se compararon las medias por la prueba de Rangos Múltiples de Duncan para un 5 % de significación estadística. El análisis se efectuó mediante el paquete estadístico SPSS versión 22.0, para Windows.

Resultados y discusión

Los datos del eflujo de iones de los 22 genotipos en estudio se muestran en la Tabla 2, se encontraron diferencias altamente significativas para este carácter, con un rango entre 14,60 a 43,18 % de eflujo. Las accesiones Ciapán 31-5 y Mex-121-A de S. pimpinellifollium fueron las de menores eflujos de iones, sin diferencias significativas con LA-2807 y P-531, accesiones pertenecientes a la forma silvestre de la especie cultivada. Los cultivares Mayle, Mercy y Yaily no mostraron diferencias con el genotipo Santa Clara.

Es de destacar que, el eflujo de iones, calculado sobre la base de los compuestos que absorben a 280 nm, es un método útil para determinar daño celular en condiciones de estrés hídrico simulado con PEG. Este método es relativamente simple, rápido y no hay fuga de electrolitos por medición de la estabilidad de la membrana (88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x ). Las diferencias encontradas entre los diferentes genotipos sugieren que esta puede utilizarse como prueba cuantitativa para determinar el efecto del déficit hídrico en tejido foliar en el tomate.

Al respecto, la mayoría de las investigaciones basan la selección para detectar genotipos tolerantes a estreses abióticos, incluido el déficit hídrico en el rendimiento del cultivo y su estabilidad en condiciones de estrés. Sin embargo, este tipo de selección que se realiza mediante pruebas en múltiples localizaciones o en diferentes años presenta baja heredabilidad (33. Jiang X, Zhao Y, Tong L, Wang R, Zhao S. Quantitative analysis of tomato yield and comprehensive fruit quality in response to deficit irrigation at different growth stages. HortScience. 2019;54(8):1409-1417. https://doi.org/10.21273/HORTSCI14180-19 , 1414. Krishna R. Ansari WA, Soumia PS, Yadav A, Jaiswal DK, Kumar S, Singh AK, Singh M, Verma JP. Biotechnological interventions in tomato (Solanum lycopersicum) for drought stress tolerance: Achievements and future prospects. BioTech. 2022;11(4):48. DOI: 10.3390/biotech11040048 , 1515. Villalobos-López MA, Arroyo-Becerra A, Quintero-Jiménez A, Iturriaga G. Biotechnological advances to improve abiotic stress tolerance in crops. International Journal of Molecular Science. 2022;23(19):12053. DOI: 10.3390/ijms231912053 ). Además, el tamizaje de la tolerancia en condiciones de campo requiere considerables recursos y condiciones ambientales precisos que puedan utilizarse para distinguir genotipos tolerantes. De ahí que con frecuencia se utilizan pruebas rápidas y menos costosas. La estabilidad de la membrana celular (CMS) es una de las más utilizadas para seleccionar genotipos tolerantes (1010. ElBasyoni I, Saadalla M, Baenziger S, Bockelman H, Morsy S. Cell membrane stability and association mapping for drought and heat tolerance in a worldwide wheat collection. Sustainability. 2017;9(9):1606-1621. https://doi.org/10.3390/su9091606 -1212. Nijabat A, Bolton A, Mahmood-ur-Rehman M, Shah AI, Hussain R, Naveed RH, Ali A, Simon P. Cell membrane stability and relative cell injury in response to heat stress during early and late seedling stages of diverse carrot (Daucus carota L.) germplasm. HortScience. 2020;55(9):1446-1452. https://doi.org/10.21273/HORTSCI15058-20 ).

Conclusiones

Introduction

Tomato (Solanum lycopersicum L.) is the second most important species within the genus Solanum spp. because of its role in the dietary habits of a large part of the world's population (11. Bayomi KEM, Abdel-Baset A, Nasar SMA, Al-Kady AEMA. Performance of some tomato genotypes under greenhouse conditions. Egyptian Journal of Desert Research. 2020;70(1):1-10. https://doi.org/10.21608/EJDR.2019.16947.1041 , 22. Monge-Pérez JE, Loría-Coto M. Determinación de criterios de selección para el rendimiento de tomate (Solanum lycopersicum L) cultivado bajo invernadero. AIA Avances en Investigación Agropecuaria. 2022;25(1):7-19.). However, crop yield is seriously affected by adverse environmental conditions, mainly water stress and extreme temperatures (33. Jiang X, Zhao Y, Tong L, Wang R, Zhao S. Quantitative analysis of tomato yield and comprehensive fruit quality in response to deficit irrigation at different growth stages. HortScience. 2019;54(8):1409-1417. https://doi.org/10.21273/HORTSCI14180-19 , 44. Sousaraei N, Mashayekhi K, Mousavizadeh SJ, Akbarpour V, Medina J, Aliniaeifard S. Screening of tomato landraces for drought tolerance based on growth and chlorophyll fluorescence analyses. Horticulture, Environment, and Biotechnology. 2021;62:521-535. https://doi.org/10.1007/s13580-020-00328-5 ).

Water stress affects the processes of transpiration, photosynthesis, stomata opening, leaf temperature and antioxidant metabolism; these metabolic changes alter plant development and compromise production and yield (55. Kumar V, Datir S, Khare T, Shriram V. Advances in biotechnological tools: Improving abiotic stress tolerance in rice. In: Hasanuzzaman M, Fujita M, Nahar K, Biswas JK, editors. Advances in Rice Research for Abiotic Stress Tolerance. Sawston, CA, USA: Elsevier Inc. 2019; Chapter 30:615-632. https://doi.org/10.1016/B978-0-12-814332-2.00030-7 -77. Méndez-Vázquez JR, Benavides-Mendoza A, Juárez-Maldonado A, Cabrera-De la Fuente M, Robledo-Olivo A, González-Morales S. Efecto del riego deficitario en la acumulación de compuestos antioxidantes en plantas de tomate. Ecosistemas y Recursos Agropecuarios. 2021;8(2):e2822. https://doi.org/10.19136/era.a8n2.2822 ). Several studies point out that membranes are the site where most stress affects plants. Losses in membrane integrity due to water stress have been assessed mostly by measuring membrane stability, and to a lesser extent by the leakage of UV-absorbing substances, including amino acids, nucleosides, and nucleotides (44. Sousaraei N, Mashayekhi K, Mousavizadeh SJ, Akbarpour V, Medina J, Aliniaeifard S. Screening of tomato landraces for drought tolerance based on growth and chlorophyll fluorescence analyses. Horticulture, Environment, and Biotechnology. 2021;62:521-535. https://doi.org/10.1007/s13580-020-00328-5 , 88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x -1212. Nijabat A, Bolton A, Mahmood-ur-Rehman M, Shah AI, Hussain R, Naveed RH, Ali A, Simon P. Cell membrane stability and relative cell injury in response to heat stress during early and late seedling stages of diverse carrot (Daucus carota L.) germplasm. HortScience. 2020;55(9):1446-1452. https://doi.org/10.21273/HORTSCI15058-20 ). The loss of UV-absorbing substances has been used to assess the relative salt stress tolerance of plant tissues, but not in water stress assessments (44. Sousaraei N, Mashayekhi K, Mousavizadeh SJ, Akbarpour V, Medina J, Aliniaeifard S. Screening of tomato landraces for drought tolerance based on growth and chlorophyll fluorescence analyses. Horticulture, Environment, and Biotechnology. 2021;62:521-535. https://doi.org/10.1007/s13580-020-00328-5 , 88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x ).

In simulation studies of water stress under laboratory conditions, polyethylene glycol (PEG) is frequently used. PEG is a polymeric alcohol with high water solubility and low toxicity that acts as a non-penetrating osmotic agent by decreasing the water potential of the culture medium; it produces a water deficiency in plant cells and an imbalance of metabolism in general (1313. Pastelín-Solano MC, Castañeda-Castro O. Afectaciones fisiológicas y bioquímicas en vitroplantas de caña de azúcar en respuesta al estrés hídrico y salino. Revista Mexicana de Ciencias Agrícolas. 2018;9(7):1483-1493. https://doi.org/10.29312/remexca.v9i7.1253 ).

Based on the above, and due to the need to look for techniques that can be used as standardized tests for tolerance to water deficit, the present work was carried out with the objective of evaluating the tolerance to this stress in leaf tissue of 22 tomato accessions by means of the relative determination of the efflux of substances that absorb UV radiation, with the purpose of identifying tolerant accessions for selection and use in genetic improvement programs.

Materials and methods

To determine the efflux of ions absorbing in UV radiation, 15 random discs of approximately 90 mm in diameter were collected from the second true leaf of 21-day-old seedlings for 22 tomato accessions; four replicates per treatment were performed (Table 1). Plant tissue was placed in 10 mL vials, washed three times with distilled water to remove external ions that might be released after cutting. They were then immersed in 2 mL of distilled water (control treatment) and 2 mL of PEG 6000 solution at 2 mPa (stress treatment), and allowed to standing in total darkness at 25 °C overnight. Subsequently, the optical density was measured at 280 nM with a Genesys 10 spectrophotometer. The efflux of phenols was calculated with the following formula (88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x ):

Where:

PE: phenol efflux

OD stress: optical density values of the stress treatments

OD control: optical density values of the control treatments

The experiment was performed in duplicate. Data were processed by simple rank ANOVA, fixed effects model and means were compared by Duncan's Multiple Range test for 5 % statistical significance. The analysis was performed using the SPSS statistical package version 22.0, for Windows.

Results and discussion

The ion efflux data of the 22 genotypes under study are shown in Table 2, highly significant differences were found for this character, with a range from 14.60 to 43.18 % efflux. The accessions Ciapan 31-5 and Mex-121-A of S. pimpinellifollium had the lowest ion efflux, with no significant differences with LA-2807 and P-531, accessions belonging to the wild form of the cultivated species. Mayle, Mercy and Yaily cultivars showed no differences with the Santa Clara genotype.

Notably, ion efflux, calculated on the basis of compounds absorbing at 280 nm, is a useful method for determining cell damage under simulated water stress conditions with PEG. This method is relatively simple, fast and there is no electrolyte leakage by measuring membrane stability (88. Redmann RE, Haraldson J, Gusta LV. Leakage of UV-absorbing substances as a measure of salt injury in leaf tissue of woody species. Physiologia Plantarum. 1986;67:87-91. https://doi.org/10.1111/j.1399-3054.1986.tb01267.x ). The differences found among the different genotypes suggest that this can be used as a quantitative test to determine the effect of water deficit in leaf tissue in tomato.

In this regard, most researches base selection for genotypes tolerant to abiotic stresses, including water deficit on crop yield and stability under stress conditions. However, this type of selection that is performed by testing at multiple locations or in different years has low heritability (33. Jiang X, Zhao Y, Tong L, Wang R, Zhao S. Quantitative analysis of tomato yield and comprehensive fruit quality in response to deficit irrigation at different growth stages. HortScience. 2019;54(8):1409-1417. https://doi.org/10.21273/HORTSCI14180-19 , 1414. Krishna R. Ansari WA, Soumia PS, Yadav A, Jaiswal DK, Kumar S, Singh AK, Singh M, Verma JP. Biotechnological interventions in tomato (Solanum lycopersicum) for drought stress tolerance: Achievements and future prospects. BioTech. 2022;11(4):48. DOI: 10.3390/biotech11040048 , 1515. Villalobos-López MA, Arroyo-Becerra A, Quintero-Jiménez A, Iturriaga G. Biotechnological advances to improve abiotic stress tolerance in crops. International Journal of Molecular Science. 2022;23(19):12053. DOI: 10.3390/ijms231912053 ). Furthermore, screening for tolerance under field conditions requires considerable resources and precise environmental conditions that can be used to distinguish tolerant genotypes. Hence, rapid and less expensive tests are often used. Cell membrane stability (CMS) is one of the most commonly used tests to select tolerant genotypes (1010. ElBasyoni I, Saadalla M, Baenziger S, Bockelman H, Morsy S. Cell membrane stability and association mapping for drought and heat tolerance in a worldwide wheat collection. Sustainability. 2017;9(9):1606-1621. https://doi.org/10.3390/su9091606 -1212. Nijabat A, Bolton A, Mahmood-ur-Rehman M, Shah AI, Hussain R, Naveed RH, Ali A, Simon P. Cell membrane stability and relative cell injury in response to heat stress during early and late seedling stages of diverse carrot (Daucus carota L.) germplasm. HortScience. 2020;55(9):1446-1452. https://doi.org/10.21273/HORTSCI15058-20 ).

Conclusions