Institute of Biology, University of Szczecin, Wąska 13, 71-415, Szczecin, Poland.
Institute of Biology, University of Szczecin, Wąska 13, 71-415, Szczecin, Poland.
J Plant Physiol. 2024 Dec;303:154363. doi: 10.1016/j.jplph.2024.154363. Epub 2024 Sep 26.
KAR, at very low concentration (3x10 M) released dormancy in Avena fatua caryopses, which was expressed in almost complete emergence of coleorhiza (CE) and radicle (RE) just after three days of germination. The dormancy-releasing effect of KAR was associated with an increased activity of ENDO-β-MANNANASE (MAN; EC 3.2.1.78) (hydrolase and transglycosylase) in coleorhiza and radicle before RE. The MAN genes, MAN1, MAN2, MAN3, MAN4, and MAN5 were for the first time identified in the genome of A. fatua. KAR induced expression of AfMAN1-3 and AfMAN5 in the coleorhiza and AfMAN2 and AfMAN3 in the radicle during caryopses germination. The increase in transcripts in the coleorhiza of AfMAN1,5 after 8 h and AfMAN3,5 after 12 h germination in the presence of KAR is probably responsible for the increase in MAN activity determined after 18 h before RE. KAR also increased AfMAN3 expression in radicle after 12 h which probably caused the increased MAN activity after 18 h. Therefore, release of caryopses dormancy by KAR involves increasing expression of MAN genes and MAN activity both in the coleorhiza and radicle, which might facilitate the passage of the radicle through the coleorhiza. The work provides the first data on the contribution of MAN, present in coleorhiza and radicle, in the dormancy release of caryopses by KAR.
KAR 在非常低的浓度（3x10-5 M）下解除了野燕麦颖果的休眠，表现在萌发后仅 3 天， coleorhiza（CE）和 radicle（RE）几乎完全出现。KAR 的休眠释放作用与 coleorhiza 和 radicle 中 ENDO-β-MANNANASE（MAN；EC 3.2.1.78）（水解酶和转糖基酶）活性的增加有关，在 RE 之前。MAN1、MAN2、MAN3、MAN4 和 MAN5 基因首次在野燕麦基因组中被鉴定出来。KAR 在野燕麦颖果萌发过程中诱导 coleorhiza 中 AfMAN1-3 和 AfMAN5 以及 radicle 中 AfMAN2 和 AfMAN3 的表达。在存在 KAR 的情况下，8 h 后 coleorhiza 中 AfMAN1、5 的转录物增加，12 h 后 AfMAN3、5 的转录物增加，这可能是 RE 前 18 h 确定的 MAN 活性增加的原因。KAR 还增加了 radicle 中 AfMAN3 的表达，这可能导致 18 h 后 MAN 活性增加。因此，KAR 通过增加 coleorhiza 和 radicle 中 MAN 基因的表达和 MAN 活性来解除颖果的休眠，这可能有助于 radicle 通过 coleorhiza。该研究首次提供了 MAN 在 coleorhiza 和 radicle 中参与 KAR 解除颖果休眠的贡献的数据。
