Expression of a gene encoding β‐ureidopropionase is critical for pollen germination in tomatoes

Abstract

Global warming has seriously decreased world crop yield. High temperatures affect development, growth and, particularly, reproductive tissues in plants. A gene encoding β-ureidopropionase (SlUPB1, EC 3.5.1.6) was isolated from the stamens of a heat-tolerant tomato (CL5915) using suppression subtractive hybridization. SlUPB1 catalyzes the production of β-alanine, the only β-form amino acid in nature. In the anthesis stage, SlUPB1 expression in CL5915 stamens, growing at 35/30°C (day/night), was 2.16 and 2.93 times greater than that in a heat-sensitive tomato (L4783) cultivated at 30/25°C or 25/20°C, respectively. Transgenic tomatoes, upregulating SlUPB1 in L4783 and downregulating SlUPB1 in CL5915, were constructed, and the amount of β-alanine measured by liquid chromatography-electrospray ionization-mass spectrometry in the transgenic overexpression of SlUPB1 was higher than that of L4783. However, the β-alanine in the transgenics downregulating SlUPB1 was significantly lower than the β-alanine of CL5915. Pollen germination rates of these transgenics were analyzed under different developmental and germinating temperatures. The results indicated that germination rates of transgenics overexpressing SlUPB1 were higher than germination rates of the background tomato L4783. Germination rates of transgenics downregulating SlUPB1 were significantly lower than germination rates of background tomato CL5915, indicating the necessity of functional SlUPB1 for pollen germination. Pollen germinating in the buffer with the addition of β-alanine further indicated that β-alanine effectively enhanced pollen germination in tomatoes with low SlUPB1 expression. Together, these results showed that the expression of SlUPB1 is important for pollen germination, and β-alanine may play a role in pollen germination under both optimal and high temperatures.

Impedance Flow Cytometry: A Novel Technique in Pollen Analysis

“…The inhibition of tomato pollen germination between 37 and 40°C is in line with previous publications demonstrating that a treatment of 38°C negatively affects pollen germination in tobacco and tomato [29,59,60]. The ability of tomato pollen to germinate after long-term storage or heat stress depends on the biosynthesis of polyamines [60,61], or β -alanine [62] with a role for specific amino acid transporters during de-/hydration phases [63]. In tobacco ( Nicotiana tabacum ) pollen specific peptides are dephosphorylated during pollen activation [28].…”

A Novel Protein Hydrolysate-Based Biostimulant Improves Tomato Performances under Drought Stress

“…Pollen viability has been recently used to identify heat-tolerant tomato genotypes, indicating pollen thermo-tolerance as an important parameter to consider for future breeding programs. Shen et al [19] indicated that the β-alanine plays a role in pollen germination under high temperatures. It is possible that the high concentration of this molecule, which is the third most representative free amino acid contained in the biostimulant (Table S3), was responsible for the higher pollen viability found in the biostimulant-treated plants.…”

Ação da insulina na captação de beta-alanina pelo músculo esquelético: efeito sobre o conteúdo de beta-alanina muscular e mecanismos envolvidos

“…Alguns estudos detectaram sua presença em folhas de tabaco, feijões, nozes, sementes de melancia, ervilhas, cevada, tomates e cenouras (Widodo et al, 2009;Leiss et al, 2013;Shen et al, 2014). No entanto, o conteúdo de β-alanina nesses alimentos é extremamente baixo, podendo ser negligenciado para fins de quantificação de seu consumo via dieta.…”