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tags | Plant Sciences and Genetics in Agriculture

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Contact Us

 

Mailing Address:
The Robert H. Smith Institute of
Plant Sciences and Genetics
in Agriculture
Herzl 229, Rehovot 7610001, Israel

Administrator: 
Neomi Maimon 
Tel: 972-8-948-9251,
Fax: 972-8-948-9899,
E-mail: neomim@savion.huji.ac.il

Secretary of teaching program:
Ms. Iris Izenshtadt
Tel: 972-8-9489333
E-mail: Iris.Izenshtadt@mail.huji.ac.il

Director: 
Prof. Naomi Ori
Tel: 972-8-948-9605
E-mail: naomi.ori@mail.huji.ac.il

 

tags

Publications

1. Zait Y., Assmann S.M. (2022) Salty or sweet? Guard cell signaling and osmotic control under saline conditions. Advances in Botanical Research, 103: 61-87.

2. Markovich O., Zexer N., Negin B., Zait Y., Blum S., Ben-Gal A., Elbaum R. (2022) Low Si combined with drought causes reduced transpiration in sorghum. Lsi1 mutant, Plant and Soil, https://doi.org/10.1007/s11104-022-05298-4.

HUJI Seminar

Dynamic regulation of leaf vascular hydraulics: molecular, cellular, and environmental factors

UC Davis Talk

Diurnal stomatal apertures and density ratios affect whole-canopy stomatal conductance, drought response, water-use efficiency and yield

Team Finds How Plants Make Aerial Roots

6 March, 2022

JUST LOOK UP!   Team Finds How Plants Make Aerial Roots

(Jerusalem, March 3, 2022)—Sometimes, to see the roots, you have to look up.

Roots are normally associated with things that live underground, in the damp and the dark. Think of turnips, radishes and yams. However, many plants make their roots above ground.  Ivy uses its roots to climb on buildings and the mighty ficus tree uses them to support their large branches.  What makes plants form roots in the “wrong place,” so to speak? That would be like us humans sprouting legs from our shoulders.

In a study published this week in the prestigious journal Science, Hebrew University of Jerusalem (HU) Professor Idan Efroni and his team found the hidden mechanism that enables aerial roots to happen. By decomposing the stem to individual cells, the team identified the extremely rare cells that, when conditions are ripe, cause roots to grow in the air.

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“Superficially, these look like other plant cells which is why they evaded detection for so long,” Efroni explained. “We used new techniques to closely screen thousands of cells, one-by-one. We knew that by finding the cells that can make roots, we would be able to look for the ‘switch’ that turns them on.”

Plants make roots from small organs called meristems.  By closely examining these unique cells, Dr. Naama Gil-Yarom, a research associate at the HU lab, was able to catch them in the act of making a meristem and to identify the genes that are active right at the transition point.  One gene in particular stood out, and when the HU PhD student Moutasem Omary used CRISPR to delete this gene, the plants lost their ability to make aerial roots.

When Efroni and his team studied the genome, they were in for a surprise. Right next to the gene that controlled aerial roots production was a very similar gene. “We recognized it immediately from previous studies as the gene that controls the formation of underground roots,” shared Efroni, “I remember thinking that we have just stumbled upon the central hub that controls root formation.” Indeed, when the researchers disabled all of these genes, the plants could not grow any roots at all.

By tracing the evolution of these genes, the team found that many major crops, such as sweet potatoes, beans, tomato, rice, maize and wheat, share this dual root-control-system. “The ability to make aerial roots is highly advantageous to the plant,” explained Efroni. “In the event that the underground roots are flooded or damaged, the plant can grow aerial roots and survive the assault,” he added.  Plants evolved this ability early on and never forgot how to do it.

Nevertheless, what is helpful in nature may actually come as a disadvantage in agriculture. Many plants are grafted, meaning they have the root system of one plant and the aboveground system of another.  This allows farmers to grow plants that are resistant to soil disease.  However, if the top part of the graft grows an aerial root, it will bypasses the soil-resistance and make all the effort of grafting useless. However, thanks to Efroni and his team’s discovery, we know which genes to target and can create plants with no aerial roots, making the practice of grafting that much more effective.

Looking ahead, the group plans to modify the DNA code at the root control cluster to make customized above- and below- ground root systems.  As Efroni concluded, “here in Israel, to make the most use of the land we’ve got, we need to optimize the way our food crops grow and utilize resources.  Doing that is a daunting and complex task, but, step by step, we’re getting there.”

CITATION:  Moutasem Omary, Naama Gil-Yarom, Chen Yahav, Evyatar Steiner, Anat Hendelman, and Idan Efroni (2022). A conserved superlocus regulates above- and belowground root initiation. Science 375: eabf4368. 10.1126/science.abf4368 

FUNDING: HHMI International Research Scholar; Israeli Science Foundation.

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How Does a Potato Feel?

25 May, 2021

Ever Wonder What A Potato Feels…?

Hebrew U. Develops Bio-Sensor to Detect Early Signs of Plant Stress
and Prevent Crop Failures from Worldwide Climate Changes

In an effort to increase agricultural productivity and limit waste, a team of researchers from the Hebrew University of Jerusalem (HU)’s Robert H. Smith Faculty of Agriculture, Food and Environment developed a method to detect signs of stress before the plant is damaged.

Conference: Plant & Ecosystem Resilience in Drylands in light of Climate Change

Save the date

יום ב' – 25 בינואר 2021
כנס מקוון (באמצעות תכנת זום ZOOM)

יציבות וכושר התאוששות הצומח והמערכות האקולוגיות באזורים יובשניים לאור שינויי אקלים
מהפרט למרחב

הרצאה מרכזית – פרופ' דן יקיר

מה יוצג? 

Negin, B. ; Yaaran, A. ; Kelly, G. ; Zait, Y. ; Moshelion, M. . Mesophyll Aba Restrains Early Growth And Flowering But Does Not Directly Suppress Photosynthesis. Plant Physiol 2019.
Abscisic acid (ABA) levels increase significantly in plants under stress conditions and ABA is thought to serve as a key stress-response regulator. However, the direct effect of ABA on photosynthesis and the effect of mesophyll ABA on yield under both well-watered and drought conditions are still the subject of debate. Here, we examined this issue using transgenic Arabidopsis thaliana plants carrying a dominant ABA-signaling inhibitor under the control of a mesophyll-specific promoter (FBPase::abi1-1, abbreviated to fa). Under normal conditions, fa plants displayed slightly higher stomatal conductance and carbon assimilation than wild-type (WT) plants; however, these parameters were comparable following ABA treatment. These observations suggest that ABA does not directly inhibit photosynthesis in the short term. fa plants also exhibited a variety of altered phenotypes under optimal conditions, including more vigorous initial growth, earlier flowering, smaller flowers and delayed chlorophyll degradation. Furthermore, under optimal conditions, fa plant seed production was less than a third of that observed for the WT. However, under drought conditions, WT and fa seed yields were similar due to a significant reduction in WT seed and no reduction in fa seed. These findings suggest that endogenous basal ABA inhibits a stress-escape response under non-stress conditions, allowing plants to accumulate biomass and maximize yield. The lack of a correlation between flowering time and plant biomass combined with delayed chlorophyll degradation suggests that this stress-escape behavior is regulated independently and upstream of other ABA-induced effects such as rapid growth and flowering.
Yaaran, A. ; Negin, B. ; Moshelion, M. . Role Of Guard-Cell Aba In Determining Steady-State Stomatal Aperture And Prompt Vapor-Pressure-Deficit Response. Plant Sci 2019, 281, 31-40.
Abscisic acid (ABA) is known to be involved in stomatal closure. However, its role in stomatal response to rapid increases in the vapor pressure deficit (VPD) is unclear. To study this issue, we generated guard cell-specific ABA-insensitive Arabidopsis plants (guard-cell specific abi1-1; GCabi). Under non-stressed conditions, the stomatal conductance (g) and apertures of GCabi plants were greater than those of control plants. This supports guard-cell ABA role as limiting steady-state stomatal aperture under non-stressful conditions. When there was a rapid increase in VPD (0.15 to 1 kPa), the g and stomatal apertures of GCabi decreased in a manner similar that observed in the WT control, but different from that observed in WT plants treated with fusicoccin. Low VPD increased the size of the stomatal apertures of the WT, but not of GCabi. We conclude that guard-cell ABA does not play a significant role in the initial, rapid stomatal closure that occurs in response to an increase in VPD, but is important for stomatal adaptation to ambient VPD. We propose a biphasic angiosperm VPD-sensing model that includes an initial ABA-independent phase and a subsequent ABA-dependent steady-state phase in which stomatal behavior is optimized for ambient VPD conditions.