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Root system of seabuckthorn (Hippophaë rhamnoides L.)

morphology, metabolism and gene expression

Shah, Syed Rehmat Ullah (2015). Root system of seabuckthorn (Hippophaë rhamnoides L.). Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2015:49
ISBN 978-91-576-8296-3
eISBN 978-91-576-8297-0
[Doctoral thesis]

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Abstract

Nutrient availability is one of the limiting factors for plant growth and development, and the nutrients on Earth are unevenly distributed. To overcome this, plants adapt by modifying their morphology and physiology, especially of the root system. Seabuckthorn is a small tree growing in temperate regions of Europe and Asia. It performs symbiotic N₂ fixation and has high adaptability to environmental constraints.

This thesis examined factors shaping the root system of seabuckthorn. It was found that seabuckthorn has the ability to produce structures with dense lateral roots called cluster roots (CRs). Different patterns of root system were found at genotype level; Pk, a wild accession of H. rhamnoides ssp. turkestanica originating from unfertile soils, produced more CRs than cultivars BHi10726 and Sunny with a breeding history in fertile soils. Reduced availability of phosphorus (P), nitrogen or iron affected root morphology by increased lateral roots and CR formation, which may explain the competitive and invasive nature of this plant on nutrient-deficient soils.

Abundant compounds in CRs found by metabolite analysis using ¹H-NMR spectroscopy were asparagine, glycine and malate, an organic acid involved in mobilization of P from soil. In Pk as compared to cv. Sunny, the concentration of root metabolites was higher. In roots under low P, RNA sequencing revealed transcripts involved in primary root metabolism, P homeostasis and metabolism consistent with a P-deficient response. To assess functions of CRs which have a determinate growth pattern, analysis of metabolites and transcripts could display changes towards a P-deficient metabolism as well as anaerobic metabolism at later developmental stages of CR. As an enzyme central to organic acid metabolism in plants, the gene family encoding phosphoenolpyruvate carboxylase (HrPPC) was characterised. Both plant-type and bacterial-type isoforms were found with tissue-specific expression patterns and with higher expression of HrPPC2 under low P. In vitro studies showed that auxin stimulated formation of lateral roots at low P levels, while high P gave high formation of shoots from roots, another trait of the seabuckthorn root system.

This study provides a basis to understand functions and roles of CRs in seabuckthorn as an actinorhizal representative among the three groups of CR-forming plants.

Authors/Creators:Shah, Syed Rehmat Ullah
Title:Root system of seabuckthorn (Hippophaë rhamnoides L.)
Subtitle:morphology, metabolism and gene expression
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :8 May 2015
Depositing date:7 May 2015
Volume:2015:49
Number of Pages:65
Papers/manuscripts:
NumberReferences
ISyed Rehmat Ullah Shah, Peter Agbäck and Per-Olof Lundquist (2015). Cluster roots of seabuckthorn (Hippophaë rhamnoides L.) in response to nitrogen, phosphorus and iron deficiency. Submitted for publication.
IISyed Rehmat Ullah Shah, Johan Meijer and Per-Olof Lundquist (2015). Analysis of plant-type and bacterial-type phosphoenolpyruvate carboxylase genes in seabuckthorn (Hippophaë rhamnoides L.) reveals tissue-specific expression of gene family members. Submitted for publication.
IIISyed Rehmat Ullah Shah, Johan Meijer, Peter Agbäck and Per-Olof Lundquist (2015). Responses of the seabuckthorn (Hippophaë rhamnoides L.) root system to phosphorus availability: Analysis of cluster root formation, metabolite and transcript patterns. Manuscript.
IVSyed Rehmat Ullah Shah, Tatiana Plaksina, Sridevy Sriskandarajah and Per-Olof Lundquist (2015). In vitro shoot organogenesis from roots of seabuckthorn (Hippophaë rhamnoides L.). Structure, initiation and effects of phosphorus and auxin. Submitted for publication.
Place of Publication:Uppsala
Publisher:Department of Plant Biology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8296-3
ISBN for electronic version:978-91-576-8297-0
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F62 Plant physiology - Growth and development
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Botany
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Developmental Biology
Agrovoc terms:hippophae, roots, root systems, plant morphology, nutrient uptake, phosphorus, iron, auxins, metabolism, gene expression
Keywords:Seabuckthorn, Hippophae, Root system, Cluster roots, Metabolism, Nutrients, Phosphorus, Phosphoenolpyruvate carboxylase, Acid phosphatase
URN:NBN:urn:nbn:se:slu:epsilon-e-2633
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-2633
ID Code:12187
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Plant Biology (from 140101)
Deposited By: Mr Syed Shah
Deposited On:08 May 2015 11:26
Metadata Last Modified:22 May 2015 21:54

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