Auxin Transport During Early Pea (Pisum sativum L.) Fruit Development

• Author / Creator

  Adihetty, Dilini D

• In pea (Pisum sativum), normal pericarp growth requires the presence of seeds and removal or abortion of seeds lead to reduced pericarp growth and subsequent abscission. Previous studies in pea showed that auxin levels are higher in seeds than the surrounding ovary (pericarp) tissues, suggesting that seeds are important to maintain the auxin pools and gradients in surrounding tissues to promote pericarp growth and development. However, further evidence for auxin transport from the seeds to the fruit and into the fruit attachment tissues (pedicel and peduncle) is required to confirm this hypothesis. To address this, we have investigated the spatial patterning of auxin activity in pericarps and associated fruit tissues using an auxin-inducible DR5:: β-Glucuronidase (GUS) reporter system in pea. We observed higher GUS staining and GUS enzyme activity in 4 days after anthesis (DAA) fruit and attached pedicel and peduncle tissues from seed-bearing fruits than those from deseeded fruits. The polar auxin transport inhibitor, N-1-naphthylphthalamic acid (NPA) applied to the peduncle attached to fruit with developing seeds increased GUS staining and GUS enzyme activity in the peduncle, pedicel and ovary (pericarp) tissues above the NPA application point. NPA application to the pericarp increased GUS staining and GUS enzyme activity within the pericarp and the seed/funiculus tissues of seeded fruits. NPA application to the peduncle, pericarp or simultaneously to the peduncle and pericarp did not induce deseeded pericarp growth. Pericarp growth was also not affected in pollinated fruits when NPA was applied at -2 DAA to either the peduncle or pedicel tissues. NPA application (at -2 DAA) to the peduncle or pedicel tissues attached to emasculated flowers, resulted in a minor increase in pericarp growth of the non-pollinated fruits, and pericarp tissue integrity was maintained up to 7 days after NPA treatment; however, the non-pollinated fruits abscised within two weeks of NPA application.
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  Overall, these data support that seeds act as a source of auxins for developing pea ovaries and fruit attachment tissues, and that auxin transport from the seeds to the fruit and attachment tissues is at least partially mediated through the polar auxin transport pathway

• Subjects / Keywords

  • Pea (Pisum sativum)
  • Auxin
  • NPA
  • Fruit development
  • GUS activity
  • GUS localization

• Graduation date

  Fall 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R39G5GW38

• License

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