Endogenous phytohormone profile during oat (Avena sativa L.) haploid embryo development

Abstract

The development of embryos requires interaction of many endogenous hormones. The aim of the study was to determine which endogenous phytohormones are involved in the process of oat (Avena sativa L.) haploidization. Oat haploids were obtained by wide crossing with Zea mays L. The hormonal profiles of the ovaries with (OE) and without developed embryo (OWE) were compared. Phytohormone contents were measured by UHPLC coupled with mass spectrometer. The total content of indole-3acetic acid (IAA), trans-zeatin (tZ), and kinetin (KN) in OE was significantly higher than in OWE. 4-Chloroindole-3-acetic acid was detected only in OWE. There were no differences between OE and OWE in the content of gibberellins (GA 1 , GA 3 , GA 4 , GA 6 , GA 7 ) and stress hormones (abscisic, salicylic, jasmonic acids). Content of endogenous KN was highly negatively correlated with the percentage of haploid embryos, germinated haploid embryos, haploid plants on MS (in vitro), haploid plants in soil (ex vitro), and doubled haploid lines. The tZ content negatively correlated with the frequency of haploid embryo formation, germination, and haploid plants obtained in vitro, as opposed to GA 1 , which correlated positively. A positive correlation was found between IAA and tZ in OE, whereas in OWE it was a negative correlation. The profiles of phytohormones in OE and OWE were determined; however, their mode of action needs to be clarified.

Anatomical and hormonal factors determining the development of haploid and zygotic embryos of oat (Avena sativa L.)

“…Oat plants intended for the production of haploid embryos were manually emasculated when half of the head was visible above the flag leaf. Then, after two days, the flowers were pollinated with maize pollen, and the next day they were treated with auxin (2,4-D) solution (100 mg dm −3 ), as previously described 7 – 9 , 12 , 22 . Twenty-one days after the pollination (DAP), enlarged ovaries were collected, individually opened under a microscope and any haploid embryos found were isolated.…”

“…Abscisic acid (ABA) acts as a GAs antagonist and its level rises when the seed enters dormancy 18 . Additionally, hormonal profiles of oat ovaries in which haploid embryos developed and ovaries in which no embryo developed were investigated, showing that the formation of a haploid embryo is accompanied by an increase in indole-3-acetic acid (IAA), trans-zeatin (t-Z), and kinetin (KN) 22 .…”

Avena fatua caryopsis dormancy release is associated with changes in KAR1 and ABA sensitivity as well as with ABA reduction in coleorhiza and radicle

“…The material was lyophilized, and 10 mg samples were pulverized with zirconia beads (MM400, Retch, Germany). ABA was analyzed as described by Dziurka et al ( 2019 ), with some modifications. Samples were spiked with 20 pmol of heavy-labelled internal standard ([ 2 H 6 ] ABA) and triple extracted in the extraction buffer (methanol/water/formic acid, 15/4/1, by vol.).…”

Auxin and its role in plant development: structure, signalling, regulation and response mechanisms

“…It was previously thought that 4-Cl-IAA was restricted to species of the Fabeae tribe within the family Fabaceae, but 4-Cl-IAA was recently detected in Medicago, Melilotus and Trifolium (Lam et al, 2016). Dziurka et al (2019) measured the auxin content (IAA, IBA and 4-Cl-IAA) in oat (Avena sativa) ovaries with or without developing embryos and observed that both IAA and IBA content was higher in developing embryos than in ovaries without developing embryos. However, 4-Cl-IAA was only detected in ovaries without developing embryos.…”

“…These results suggest that both IAA and IBA are involved in embryonic development, whereas 4-Cl-IAA is an important signalling molecule for oat floret senescence. However, the precise mechanisms of action of these hormones remain unknown (Dziurka et al (2019).…”