Arabidopsis and sunflower plants with increased xylem area show enhanced seed yield. (23rd May 2019)

• Record Type: Journal Article
• Authors: Cabello, Julieta V.; Chan, Raquel L.
• Is Part Of: Plant journal. Volume 99:Number 4(2019)
• Page Start: 717
• Page End: 732
• Publication Date: 2019-05-23
• Subjects: vascular bundles -- xylem area -- auxin carriers -- seed yield -- LAX2 -- mechanical treatment -- Arabidopsis thaliana -- Helianthus annuus; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.14356
• Languages: English
• ISSNs: 0960-7412

Abstract

Summary: Plant architecture plasticity determines the efficiency at harvesting and plays a major role defining biomass and seed yield. We observed that several previously described transgenic genotypes exhibiting increased seed yield also show wider stems and more vascular bundles than wild‐type plants. Here, the relationship between these characteristics and seed yield was investigated. Hanging weight on the main stem of Arabidopsis plants provoked significant stem widening. Such widening was accompanied by an increase in the number of vascular bundles and about 100% of yield increase. In parallel, lignin deposition diminished. Vascular bundle formation started in the upper internode and continued downstream. AUX/LAX carriers were essential for this response. The increase of vascular bundles was reverted 3 weeks after the treatment leading to an enlarged xylem area. Aux1, lax1, and lax3 mutant plants were also able to enlarge their stems after the treatment, whereas lax2 plants did not. However, none of these mutants exhibited more vascular bundles or seed yield compared with untreated plants. Weight‐induced xylem area enhancement and increased seed yield were also observed in sunflower plants. Altogether these results showed a strong correlation between the number of vascular bundles and enhanced seed yield under a long‐day photoperiod. Furthermore, changes in the levels of auxin carriers affected both these processes in the same manner, suggesting that there may be an underlying causality. Significance Statement: The transient formation of additional vascular bundles can be induced by a short hanging weight treatment triggering the expansion of xylem area and ultimately seed yield.