光对海带雌、雄配子体lhcf5和lhcf6基因相对转录量的影响

Effects of light on the relative transcription of lhcf5 and lhcf6 genes from the gametophytes of Laminaria japonica

利用实时荧光定量PCR(Q-RT-PCR)方法分析了在不同光照强度、光质及有利于配子产生的条件下,lhcf5和lhcf6基因在海带(Laminaria japonica)雌、雄配子体中转录量的变化。不同光照强度条件下(光源为白光),lhcf5和lhcf6基因在黑暗中接近不转录;雌配子体在光照强度40μmol·m-2·s-1时转录量最高,而雄配子体的最高转录量出现在80μmol·m-2·s-1的光照强度处;高于此光照强度,2个基因的转录量都会随光照强度增加而降低。相对于同强度的白光来说,红光照射无论是短时间(3d)还是长时间(7d),都会促进2个基因的相对转录水平;蓝光对雌配子体中2个基因转录的促进作用不明显,而对它们在雄配子体中的转录有一定的促进作用。将海带配子体从营养生长转至有利于配子发生的条件下,雌、雄配子体lhcf5和lhcf6基因在第1天的转录量都明显增加;雌配子体在第4天以及第12天(lhcf6)或第14天(lhcf5)均显著增加,第6天及第10天接近不转录;雄配子体在第8天及第14天增加,第10天也近似不转录;发育阶段其他时间内的转录量都低于营养生长期的。结果表明,海带配子体lhcf5和lhcf6的转录受光诱导,其中红光的促进作用最明显;其转录可能因有利于配子体细胞叶绿体结构的完善及物质与能量的积累而利于细胞分裂与营养生长。

The relative transcription of lhcf5 and lhcf6 genes between male and female gemetophytes of Laminaria japonica grown under different wave lengths of light,light intensities and the conditions favorable for the gametogenesis was estimated by using quantitative real-time PCR（Q-RT-PCR）.The lhcf5 and lhcf6 genes were transcribed very little at dark.They reached a maximum in transcription under 40μmol·m -2 ·s -1 in males,and under 80μmol·m -2 ·s -1 in females.When light irradiance was higher than the most moderate one,the relative transcription level of lhcf5 and lhcf6 genes decreased while light intensity increased.Compared to the illumination only with white light at the same irradiance,red light could significantly promote the relative transcription of the two genes for a both short（3 d）and long（7 d）illumination time.Blue light had a positive effect on promoting transcription of the two genes in the male gametophytes,on the contrary,its effect on females was not clear.When transferred to the conditions favorable for gametogenesis from vegetative growth,both male and female gametophytes showed a remarkably increased transcription level of lhcf5 and lhcf6 genes on the first day.In addition,lhcf6 and lhcf5 genes were transcribed higher on days 4 and 12（lhcf6）or day 14（lhcf5）in female gametophytes,even if then were nearly not transcribed on Days 6 and 10.By contrast,there was an increase of the transcription of these genes on Day 8 and 14 in males,even if they were nearly not transcribed on Day 10.These manifested a lower transcription level on other days during the developmental stages than that of the vegetative growth period.These results suggest that the regulation of lhcf5 and lhcf6 genes can be induced by light,among which red light can promote the transcription level significantly.It was further deduced that the transcription of lhcf5 and lhcf6 genes is not only helpful to cellular substance and energy storage but also to construction of chloroplast of the gametophytes,all providing good materials to cell division and vegetative growth.