Trans-Zeatin induce regulation the biosynthesis of 2-acetyl-1-pyrroline in fragrant rice (Oryza sativa L.) seedlings

Abstract

Background In plants, cytokinin is activated into trans-zeatin to fight abiotic stresses. However, the mechanism of the effect of trans-zeatin on 2-acetyl-1-pyrroline (2-AP) biosynthesis in fragrant rice has yet to be studied. The present study was conducted to explore the effects of exogenous trans-zeatin on enzymes activities, genes expression, and precursors involved in 2-AP biosynthesis and 2-AP contents as well as the seedling quality of a fragrant rice cultivar viz., Meixiangzhan2. Four concentrations of trans-zeatin solutions at 20, 40, and 80 μmol L− 1 (ZT1, ZT2, and ZT3) were sprayed onto rice seedlings. Results Compared to the control, trans-zeatin treatments showed significantly higher 2-AP contents of fragrant rice seedlings. Increased plant height and stem width were observed due to trans-zeatin treatments. The trans-zeatin application increased 1-pyrroline, methylglyoxal, proline, and P5C contents, enhanced P5CS and OAT activities, and reduced glutamic acid contents. In addition, expressions of ProDH, P5CS2, and DAO4 were comparatively higher under trans-zeatin treatments than CK in fragrant rice seedlings. Conclusions Overall, up-regulation of P5C, 1-pyrroline, and proline and down-regulation of glutamic acid under appropriate trans-zeatin concentrations (20 and 40 μmol L− 1) resulted in enhanced 2-AP biosynthesis in fragrant rice seedlings and 20–40 μmol L− 1 was considered as the suggested concentrations of trans-zeatin application in fragrant rice seedling.

Effects of paclobutrazol seed priming on seedling quality, photosynthesis, and physiological characteristics of fragrant rice

“…Although glutamic acid and proline are precursors of 2-AP, proline plays a more critical role in aroma synthesis [ 25 ]. Similar to the experimental results of spraying trans zeatin on fragrant rice seedlings, the glutamic acid content in fragrant rice seedlings decreased [ 26 ]. However, the content of proline and 2-AP significantly increased.…”

Regulation of 2-Acetyl-1-pyrroline Content in Fragrant Rice under Different Temperatures at the Grain-Filling Stage

“…15,30,31 The results of our study showed that there existed a significant and negative relationship (correlation coefficient < −0.5) between 2-AP content and BADH2 expression, which also agreed with our previous findings. 7,32 On the other hand, the content of GABA, which could be formed by BADH2, decreased with increased temperature and showed a positive correlation (correlation coefficient > 0.5) with 2-AP content. This finding was inconsistent with the study by Bao et al 7 but agreed with the study by Mo et al 1 GABA content has been shown to respond to stresses, and our results were consistent with an earlier study which indicated temperature-induced regulation of GABA metabolism in plants.…”

l-Glutamate Seed Priming Enhances 2-Acetyl-1-pyrroline Formation in Fragrant Rice Seedlings in Response to Arsenite Stress

“…The present performance in VIP scores (Figure 1d−g) agreed that 2-AP was recognized as the pivotal compound of aroma in fragrant rice, physiologically, being determined by the activities of ProDH, P5CS, OAT, the content of Pro, P5C, and MG. 1,30,37,38 The resultant Glu100 and Glu500 treatment increased the P5C, MG content, P5CS, ProDH, and OAT activities with similar trends of mRNA transcription levels for 2-AP accumulation (SI, Figure S3cd,f−k), which were coordinated with the studies of exogenous application on fragrant rice to improve the 2-AP. 4,39,40 It was inferred that exogenous Glu might up-regulate OAT, inducing the Glu and Pro catabolism and accumulation to resume 2-AP biosynthesis at As stress defense level (Figure 4, and SI, Figure S6).…”