Deciphering the localization and concentration of arsenic in nodules of peanut plants affected by combined metalloid and flooding stress

BIANUCCI ELIANA; PAULA PONGREAC; KATARINA HROVAT; KATARINA VOGEL-MIKU?; PRIMO? PELICON; MITJA KELEMEN; PRIMO? VAVPETIč; ANA FURLAN; CHARLOTTE POSCHENRIEDER

Encuentro; RADIATE Midterm Meeting; 2022

Natural combined stresses are challenging the sustainability of agro-ecosystems affecting significantly crops every year. Arsenic (As) presence in groundwater represents a global problem due to human contamination and the occurrence of flooding aggravates the situation. In Argentina, several cropping areas are affected by flooding episodes, which increase As-containing groundwater level. When reaching the rhizosphere, As is easily absorbed by plants and this uptake constitutes the first step of tropic chain contamination. Peanut (Arachis hypogaea L.) is an economically important legume crop. In Argentna its production is mainly located in Córdoba province, where 90% of the groundwater contains high As levels and flooding episodes are frequent. This legume engages in a symbiotic interaction with Bradyrhizobium sp. members that improves plant nitrogen (N) supply by the biological N fixation with the formation of a new organ in the root, the nodule. A large amount of elements is needed to assure this process functions, for example nitrogenase enzyme complex is iron (Fe) and molybdenum-dependent. Several abiotic stresses, such as As and flooding, affect nutrient uptake by plant roots and this could lead to an alteration of essential element distribution within the nodule. Thus, to analyze element disturbances on peanut nodules, plants inoculated with Bradyrhizobium sp. SEMIA6144 were exposed to As, flooding and the combined stress. Using X-ray fluorescence, we could determine, the concentration of As and also phosphorus (P), sulphur (S), chlorine (Cl), potassium (K), calcium (Ca), Fe and zinc (Zn); and using quantitative micro-particle induced X-ray emission we could locate the mentioned elements at tissue level. Resolving the localization and distribution of As and other essential elements in peanut nodules, will significantly contribute to the knowledge of the disturbances caused by these stresses in peanut crop. These results may also contribute to finding novel strategies to avoid crop contamination by toxic elements