Jiao Jiao, Wang Ji, Zhou Mengjia, Ren Xuyang, Zhan Wenyue, Sun Zongjiu, Zhao Haiyan, Yang Yao, Liang Mingxiang, den Ende Wim Van
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China.
Jiangsu Key Lab of Marine Biology, Nanjing, China.
Front Plant Sci. 2018 Sep 19;9:1384. doi: 10.3389/fpls.2018.01384. eCollection 2018.
The inulin-type fructans in Jerusalem artichoke ( L.) tubers exhibit different degrees of polymerization and are critical for germination. We aimed to characterize the sugar metabolism dynamics in the tubers without bud eyes or shoots (T) and BE/S of indoor- and field-grown Jerusalem artichokes during germination. and (1-fructan exohydrolases II and III, inulin-degrading enzymes) expression increased 5 days after planting indoors, whereas expression increased 72 days after planting in the field in T and BE/S. (sucrose:sucrose 1-fructosyl transferase, inulin synthesis initiator), and (fructan:fructan 1-fructosyl transferase, inulin elongator) expression generally decreased in indoor-grown T. The enzyme activities of 1-FEH and 1-FFT were unchanged during germination in both indoor- and field-grown T and BE/S, whereas 1-SST activity decreased in indoor-grown T, while 1-FEH and 1-FFT activities increased as a function of germination time in BE/S of both indoor- and field-grown tubers. The total soluble sugar content gradually decreased in T after germination indoors or in the field, while at the end of germination, the sucrose and fructan contents decreased, and fructose content increased in the field. The enzyme activities of soluble vacuolar (VI) or neutral invertase (NI) did not change significantly, except at the late germination stage. Sucrose synthase (SS) and sucrose-phosphate synthase (SPS) activities were not significantly changed in T and BE/S in indoor-grown artichokes, while SS activity gradually increased, and SPS activity gradually decreased in field-grown artichokes, alongside sucrose degradation. Compared to T, BE/S generally had higher enzyme activities of 1-FEH and 1-FFT, promoting inulin hydrolysis. This work shows that the process of tuber germination is similar indoors and in the field, and germination studies can therefore be conducted in either environment.
菊芋（L.）块茎中的菊糖型果聚糖具有不同程度的聚合度，对发芽至关重要。我们旨在表征室内和田间种植的菊芋在发芽过程中无芽眼或芽的块茎（T）以及带芽眼/芽的块茎（BE/S）中的糖代谢动态。1 - 果聚糖外切酶II和III（1 - fructan exohydrolases II and III，菊粉降解酶）的表达在室内种植后5天增加，而在田间种植的T和BE/S中，其表达在种植72天后增加。蔗糖：蔗糖1 - 果糖基转移酶（sucrose:sucrose 1 - fructosyl transferase，菊粉合成起始酶）和果糖基转移酶（fructan:fructan 1 - fructosyl transferase，菊粉延伸酶）的表达在室内种植的T中总体下降。在室内和田间种植的T和BE/S发芽过程中，1 - FEH和1 - FFT的酶活性均未改变，而在室内种植的T中1 - SST活性下降，在室内和田间种植块茎的BE/S中，1 - FEH和1 - FFT活性随着发芽时间而增加。在室内或田间发芽后，T中的总可溶性糖含量逐渐降低，而在发芽末期，田间的蔗糖和果聚糖含量降低，果糖含量增加。可溶性液泡（VI）或中性转化酶（NI）的酶活性除在发芽后期外无显著变化。在室内种植的菊芋中，T和BE/S中的蔗糖合酶（SS）和蔗糖磷酸合酶（SPS）活性无显著变化，而在田间种植的菊芋中，随着蔗糖降解，SS活性逐渐增加，SPS活性逐渐降低。与T相比，BE/S通常具有较高的1 - FEH和1 - FFT酶活性，促进菊粉水解。这项工作表明，块茎发芽过程在室内和田间相似，因此可以在任何一种环境中进行发芽研究。
