Memoria para optar al título profesional de Ingeniero Agrónomo / El cultivo de la jojoba ((Simmondsia chinensis (Link.) Schneider) se caracteriza por una alta sensibilidad al anegamiento, una alta tolerancia a la salinidad y al déficit hídrico. Es así como en una plantación de jojoba, ubicada en Diego de Almagro, región de Atacama y regadas con aguas claras del tranque de relaves mineros Pampa Austral (con altas concentraciones de sales y metales pesados), se presento una elevada y aleatoria muerte de plantas asociada a lluvias invernales del 2009. De esta forma se estudió el efecto de la simulación de precipitaciones y la salinidad del suelo sobre la planta. Se aplicaron cuatro tratamientos con un diseño experimental en boques completos al azar con arreglo factorial, donde los factores fueron salinidad (lugar de aplicación de los tratamientos) y cantidad de agua aplicada como simulación de lluvia, donde los tratamientos fueron: suelo sin sales y anegamiento (SS/LL); suelo sin sales y simulación de anegamiento (SS/A); suelo con sales y simulación de lluvia (CS/LL); Suelo con sales y simulación de anegamiento (CS/A) Se realizo un seguimiento del comportamiento del suelo (humedad, temperatura y conductividad eléctrica), de la condición fisiológica de la planta (Fluorescencia de clorofilas, temperatura foliar y potencial hídrico de brote) y un estado general de la planta (crecimiento, daño y mortalidad). Se vio diferencia entre las humedades entre hilera para los dos lugares de aplicación (factor salino), las plantas más afectadas fisiológicamente fueron las del tratamiento CS/A, del mismo modo que el crecimiento y desarrollo de las mismas, Presentando una relación inversa entre la fluorescencia de clorofilas y el daño en la planta. Permitiendo concluir que existe un efecto combinado de anegamiento radical y desplazamiento de sales sobre el funcionamiento fisiológico de la plantas de jojoba.

Seeds from the desert shrub Simmondsia chinensis (jojoba) are one of the only known natural plant sources to store a majority of its oil in the form of liquid wax esters (WE) instead of triacylglycerols (TAGs) and these oils account for ~55% of the seed weight. Jojoba oil is highly valued as cosmetic additives and mechanical lubricants, yet despite its value much is still unknown about its neutral lipid biosynthetic pathways and lipid droplet packaging machinery. Here, we have used a multi-"omics" approach to study how spatial differences in lipid metabolites, gene expression, and lipid droplet proteins influence the synthesis and storage of jojoba lipids. Through these studies mass spectrometry analyses revealed that WEs are compartmentalized primarily in the cotyledonary tissues, whereas TAGs are, surprisingly, localized to the embryonic axis tissues. To study the differences in gene expression between these two tissues, a de novo transcriptome was assembled from high throughput RNAseq data. Differential gene expression analysis revealed that the Jojoba Wax Synthase, which catalyzes the formation of wax esters, and the Diacylglycerol O-Acyltransferase1, which catalyzes the final acylation of triacylglycerol synthesis, were differentially expressed in the cotyledons and embryonic axis tissues, respectively. Furthermore, through proteomic analysis of lipid droplet proteins from lipid droplets of the cotyledons and embryonic axis, it was estimated that each of these tissues contains a different proportion of the major lipid droplet proteins, oleosins, steroleosins, caleosins, and lipid droplet associated proteins. The Jojoba Olesosin1, Lipid Droplet Associated Protein 1, and Lipid Droplet Associated Protein 3, were identified as potential lipid droplet proteins that could be important for storage of wax esters. The coding sequences of these genes were transiently expressed in N. benthamiana leaves individually, and with co-expression of Mus musculus diacylglycerol acyltransferase 2, and in all cases were able to induce neutral lipid accumulation. These data also suggest a Lipid Droplet Associated Protein 1 has a specialized role for wax ester accumulation in the cotyledons, whereas Lipid Droplet Associated Protein 3 may have a more generalized role for the storage of triacylglycerols. These differences in compartmentation suggests that the cotyledons and embryonic axis of jojoba have evolved tissue-specific sets of genes for neutral lipid assembly and lipid droplet accumulation. It may be important to consider this tissue context for genetic engineering strategies designed to introduce genes from jojoba into other oilseed crops.