Zea nicaraguensis, a wild relative of maize, forms a strong barrier to radial oxygen loss in both the main axis and laterals of adventitious roots during waterlogging

TY - ABST

T1 - Zea nicaraguensis, a wild relative of maize, forms a strong barrier to radial oxygen loss in both the main axis and laterals of adventitious roots during waterlogging

AU - Kurokawa, Yusuke

AU - Hiroki, Yasue

AU - Nakayama, Yohei

AU - Watanabe, Kohtaro

AU - Takahashi, Hirokazu

AU - Floytrup, Anja

AU - Omori, Fumie

AU - Mano, Yoshiro

AU - Colmer, Timothy David

AU - Pedersen, Ole

AU - Nakazono, Mikio

PY - 2019/6/2

Y1 - 2019/6/2

N2 - Zea nicaraguensis, a wild relative of Zea mays ssp. mays (maize), shows high waterlogging tolerance compared to maize. Tolerance is associated with a superior ability to supply oxygen to the tips of roots. When waterlogged, Z. nicaraguensis forms aerenchyma and a tight barrier to radial oxygen loss (ROL) in the basal parts of the adventitious roots; the ROL barrier greatly restricts oxygen leakage from root to rhizosphere. In stark contrast, maize is unable to form a tight ROL barrier in the adventitious roots, but does form aerenchyma. Lateral roots can play an important role absorbing water and nutrients, but whether the laterals can form a ROL barrier had not been investigated. In this study, we assessed ROL barrier formation in the lateral roots of maize (inbred line Mi29) and Z. nicaraguensis. The staining of the lateral roots with an oxygen indicator dye revealed that only the most apical portion of the lateral roots in Z. nicaraguensis showed substantial leakage of oxygen, whereas for maize the entire lateral root from the base to the apex leaked oxygen to the rhizosphere. These different ROL profiles of Z. nicaraguensis and maize lateral roots were confirmed by measurements taken with root-sleeving oxygen electrodes and by microelectrode-profiling into lateral roots. Suberin staining of the lateral roots, which is considered to be a candidate component contributing to ROL barrier formation, revealed that suberin was deposited on the exodermis/hypodermis of the lateral roots in both Z. nicaraguensis and maize suggesting that the tight ROL barrier in Z. nicaraguensis is not only due to simple suberin deposition.

AB - Zea nicaraguensis, a wild relative of Zea mays ssp. mays (maize), shows high waterlogging tolerance compared to maize. Tolerance is associated with a superior ability to supply oxygen to the tips of roots. When waterlogged, Z. nicaraguensis forms aerenchyma and a tight barrier to radial oxygen loss (ROL) in the basal parts of the adventitious roots; the ROL barrier greatly restricts oxygen leakage from root to rhizosphere. In stark contrast, maize is unable to form a tight ROL barrier in the adventitious roots, but does form aerenchyma. Lateral roots can play an important role absorbing water and nutrients, but whether the laterals can form a ROL barrier had not been investigated. In this study, we assessed ROL barrier formation in the lateral roots of maize (inbred line Mi29) and Z. nicaraguensis. The staining of the lateral roots with an oxygen indicator dye revealed that only the most apical portion of the lateral roots in Z. nicaraguensis showed substantial leakage of oxygen, whereas for maize the entire lateral root from the base to the apex leaked oxygen to the rhizosphere. These different ROL profiles of Z. nicaraguensis and maize lateral roots were confirmed by measurements taken with root-sleeving oxygen electrodes and by microelectrode-profiling into lateral roots. Suberin staining of the lateral roots, which is considered to be a candidate component contributing to ROL barrier formation, revealed that suberin was deposited on the exodermis/hypodermis of the lateral roots in both Z. nicaraguensis and maize suggesting that the tight ROL barrier in Z. nicaraguensis is not only due to simple suberin deposition.

KW - Faculty of Science

KW - rice

KW - ROL

KW - internal aeration

KW - flooding stress

KW - flooding tolerance

KW - flood tolerant

KW - maize

KW - teosinte

KW - oxygen

M3 - Conference abstract for conference

T2 - 2019 ISPA Conference

Y2 - 2 June 2019 through 5 June 2019

ER -