Abscisic acid phytohormone estimation in tubers and shoots of Ipomoea batatas subjected to long drought stress using competitive immunological assay.

Carla S S Gouveia,Jan J Slaski,José F T Ganança,Miguel Â A Pinheiro De Carvalho,Vincent Lebot

doi:10.1111/ppl.13192

Carla S S Gouveia, Jan J Slaski + Show 3 more

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https://doi.org/10.1111/ppl.13192

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Abstract

Sweet potato (Ipomoea batatas L.), typically cultivated in temperate climates under low inputs, is one of the most important crops worldwide. Abscisic acid (ABA) is an important plant stress-induced phytohormone. Hitherto, few works analyzed the ABA function in sweet potato tissue growth. Very scarce information is available concerning the ABA role in sweet potato response to water scarcity conditions. Here, we show the ABA content variation in shoots and tubers of eight sweet potato accessions subjected to drought stress. ABA was also related to other resistance traits, such as chlorophyll content index (CCI), carbon isotopic discrimination (Δ13 C), oxalic acid (OA) and water use efficiency (WUE), to assess stress response mechanisms to water deficit between their organs. The most resilient drought-stressed sweet potato plants accumulated ABA-shoot, and significantly decreased the ABA-tuber content. ABA signaling was related to Δ13 C and CCI decrease and WUE increment, as an attempt to cope with water stress by partially closing the stomata. The partial closure of stomata could be in part due to the presence of OA-shoots, known to affect the intensity of the ABA-shoot signal in stomatal closure. Higher CCI content and minimal Δ13 C-shoot differences indicated good carboxylation fractionation, with higher Δ13 C-tuber content as an indicator of efficient tuber 13 C fixation and growth. Our work demonstrated that ABA could be used in conjunction with the other traits studied for the assessment of sweet potato whole-plant responses to environmental stresses, and thus aid the selection of the best drought tolerant genotypes for breeding programs.

Highlights

Sweet potato [Ipomoea batatas (L.) Lam.], after potatoes (Solanum tuberosum L.) and cassava (Manihot esculenta Crantz) root tubers, is one of the most important staple crops in the world (Lebot 2009, FAOSTAT StatisticalDatabase 2018)
Analysis of variance and correlations, it was shown how the differences of Abscisic acid (ABA) content in eight sweet potato accessions grown under water scarcity were related to the chlorophyll content index (CCI), carbon isotope discrimination (Δ13C), oxalic acid (OA) and water use efficiency (WUE)
The ABAshoot accumulation was correlated with Δ13C-shoot and OA decrease

Summary

Introduction

Sweet potato [Ipomoea batatas (L.) Lam.], after potatoes (Solanum tuberosum L.) and cassava (Manihot esculenta Crantz) root tubers, is one of the most important staple crops in the world (Lebot 2009, FAOSTAT StatisticalDatabase 2018). Sweet potato [Ipomoea batatas (L.) Lam.], after potatoes (Solanum tuberosum L.) and cassava (Manihot esculenta Crantz) root tubers, is one of the most important staple crops in the world Sweet potato is an important food source supply in tropical and developing countries owing to the storage of 80–90% carbohydrates in root dry matter content (Lebot 2009). Some countries use the sweet potato leaves as a vegetable source, providing high. The major sweet potato production occurs in Asia, with 60.7 Mt in 2018, representing 66% of worldwide production (FAOSTAT Statistical Database 2018). With the characteristic low plant growth habit and extensive root system, the sweet potato can be moderately tolerant to water scarcity (Smittle et al 1990, Ekanayake and Collins 2004, Motsa et al 2015a, 2015b). The exposure to an extended period of abiotic stress leads to plant physiological modifications, changing the crop quality and biochemical composition to cope and survive stress (Wang and Frei 2011)

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