Actually I developed this doubt while solving some questions(they are poorly framed I suspect). According to my notes and my institute modules, 1 RNA primer is required on the leading strand as well to start DNAP activity, and at the end repairing enzyme will remove the primer and add the complementary nucleotides. Now, here's the problem i am facing, will the DNA ligase join the newly added nucleotides by the correction enzyme or it is not required? The questions that created this doubt say in the solutions that DNA ligase is not a requirement in replication on leading strand but i think it should be required to join the nucleotides added by the correction enzyme as is the case on lagging strand. Am i correct?
The work of DNA ligase is to form "phospho-ester bond" or "phospho-diester bond"(bond joining phosphate of one nucleotide with OH of another nucleotide).
by forming this bond the DNA ligase seals gap b/w 2 nucleotide sequence.
Now in case of lagging strand okazaki fragments are formed and gap b/w two okazaki fragments are filled by DNA polymerase and then the final joint is done by DNA ligase by forming phospho-ester bond b/w a nucleotide(last nucleotide which was placed by DNA Polymerase)and another nucleotide (which is the first nucleotide in the nucleotide sequence of second okazaki fragment which is being joined together)
now there is no need of all this mechanism in case of leading strand because there is no okazaki fragment present in leading strand. So DNA ligase is NOT required in case of leading strand.
hope this helps!!
as discussed in the comments below, the DNA ligase might be required in joining two leading strands of two replication fork of a replicon