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Israel Agriculture 2014

Improving fertilization

efciency leads to

increased yields and fruit Martin Goldway, Raf A. Stern,
Doron Schneider, Amir Raz and
Annat Zisovich
MIGAL Galilee Research Institute,
quality of orchards in the Kiryat Shmona 11016, Israel,
and the Department of
Biotechnology, Faculty of Life
Galilee Sciences, Tel-Hai College, Upper
Galilee 12210, Israel

Fig 1: a) Schematic description of levels of compatibility between pollen and pistil in the S-RNase-mediated self-incompatibility system (see text
for explanation). b) A peach fower

The Galilee is the main fruit-producing region in Israel. they relate to yield defciencies.
Most of the varieties grown there are of the botanical family Because of the dependence on cross-pollination, orchards
Rosaceae, namely: apple, pear, apricot, plum, cherry, peach, contain a least two cultivars that fower synchronously
loquat and almond. Although the fowers of these fruit trees and are genetically compatible. Self-incompatibility is
have both male (pollen) and female (pistil) components, determined by an RNase-mediated mechanism which is
they are self-incompatible-the fower does not fertilize itself. carried by the S-locus. In addition to the S-RNase, the S-locus
Hence, fertilization is achieved by cross-pollination with contains a few SFB genes that hold an F-box motif which is
another cultivar. a component of the E3 ligase of the ubiquitin proteasome
system. This system, which targets proteins for degradation,
Despite the excellent standards of the Israeli farmer, a
comparison to the same cultivars grown in other regions was identifed by the Israelis Hershko and Ciechanover, for
of the world ofen shows lower yields and smaller fruits which they received the Nobel Prize.
in Israel. Since these fruit trees originate from temperate The basic model for the RNase-mediated self-incompatibility
climates, research is focusing on the tree features that are system proposes that S-RNase is secreted from the style
most afected by the suboptimal Mediterranean climate. Our cells and enters the pollen tube. The RNases cytotoxicity
group is investigating fertilization and pollination aspects as (degrading the pollens RNA) halts pollen growth and

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