Roles of Phospholipases in Response to Freezing

To this end, lipidomics profiling of plant samples carrying PLD mutants in comparison to wild-type counterparts provided great insights into the cellular functions of different PLD isoforms [17,55], For example, lipidomics analysis greatly revealed the different roles of PLDs in freezing-induced lipid hydrolysis [6, 65], 

So next question is which PLD isoform(s) play the essential role in plants in response to low temperatures, leading to the increase in the levels of PA species. Further studies by lipidomics revealed that suppression of PLDal led to a higher level of PC species, but a lower level of PA species [6], These results indicated that PC was the major in vivo substrate for PLDal under freezing conditions. In fact, PLDal was responsible for 50% of PC hydrolyzed under the freezing conditions tested [6], The lack of difference between wild-type and PLDal-deficient plants in the levels of PE and PG species suggests that other enzymes in addition to PLDal were responsible for the freezing-induced hydrolysis of PE and PG species. 

3 Role of PLDt in Phosphorus Deficiency-Induced Lipid Changes As 

DAG species for galactolipid biosynthesis. Then, the question is what causes the loss of GPL content under phosphorus deficiency conditions. Further studies by lipidomics [65, 66] revealed that the loss of PLDi, but not PLDi l, led to a significantly decreased accumulation of PA content in roots under phosphorus deficiency conditions and compromised the ability of plants to hydrolyze GPLs and to increase galactolipid levels. Moreover, plants null of PLD l and PLD( 2 exhibited shorter primary roots than wild-type plants under the phosphoras deficiency conditions. These results indicate that PLD l and PLDt play an important role in regulating root development in response to nutrient limitation. 

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