Plant Hormone Transport – Plant growth and development is mediated to a large extent by hormones. Plants regulate hormone response pathways at multiple levels including biosynthesis, metabolism, perception, and signaling. javascript:void(null);In addition, plants exhibit the unique ability to spatially regulate hormone distribution. This ability is illustrated most clearly in the case of auxin (IAA). The combined activity of auxin influx and efflux carrier proteins generates auxin maxima and local gradients that inform developmental patterning. The regulation of the cellular localization of PIN-FORMED (PIN) efflux transporters determines the direction of auxin flow from one cell to another. Until recently, little was known about the transport mechanisms and the distribution patterns of hormones other than auxin. These are exciting days for the plant hormone community as novel gibberellin (GA), abscisic acid (ABA), and cytokinin (CK) transporters are currently been identified, joining earlier findings on auxin transporters.

We are interested in the molecular factors regulating plant hormones transport mechanisms. We study the first events of cellular signaling – all the way to the patterning of the whole plant, primarily focusing on the plant hormones auxin, abscisic acid and gibberellin.

Redundancy of plant genomes – Plant genomes are highly redundant. For example, 80% of Arabidopsis genes (22,020 of the ~25,500 total genes) belong to families with at least two members. As a result, most single null mutants do not present an evident phenotype as the overlapping function of one or more paralogs mask any effects. During the past two decades, genetic variation and forward genetics screen have been expanded by creating random mutagenized lines using chemical or radiation treatments leading to the identification of novel genetic processes. However, these approaches cannot overcome the genetic redundancy problem a large fraction of the potential phenotypic plasticity is “hidden”.

We aim to Investigate how plants balance robustness and specialization in hormone transport at the cellular and subcellular levels. Our group places key technological challenges that require interdisciplinary expertise to overcome the long-standing obstacle of functional redundancy in plants. We use genome-scale artificial microRNAs (amiRNAs) and CRISPR technologies to generate mutants that allow us to identify the missing redundant hormone transporters to investigate the biological relevance of such specialized activity. In vitro transport assays and analyses of in vivo physiological responses reveal how gene families have developed complex robustness but diverse specialization.

Email: eilonsh@tauex.tau.ac.il
Phone: 03-6409125
Office: Britannia-Porter, 511